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Prof. Dr. Simona Carfagna
Department of Biology, University of Naples Federico II, Napoli, Italy

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0 Oxidative Stress
0 Pigments
0 extremophiles
0 Plant Mineral Nutrition
0 Unicellular algae

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Journal article
Published: 11 February 2021 in Plants
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Pancratium maritimum (Amaryllidaceae) is a bulbous geophyte growing on coastal sands. In this study, we investigated changes in concentrations of metabolites in the root and leaf tissue of P. maritimum in response to mild salt stress. Changes in concentrations of osmolytes, glutathione, sodium, mineral nutrients, enzymes, and other compounds in the leaves and roots were measured at 0, 3, and 10 days during a 10-day exposure to two levels of mild salt stress, 50 mM NaCl or 100 mM NaCl in sandy soil from where the plants were collected in dunes near Cuma, Italy. Sodium accumulated in the roots, and relatively little was translocated to the leaves. At both concentrations of NaCl, higher values of the concentrations of oxidized glutathione disulfide (GSSG), compared to reduced glutathione (GSH), in roots and leaves were associated with salt tolerance. The concentration of proline increased more in the leaves than in the roots, and glycine betaine increased in both roots and leaves. Differences in the accumulation of organic osmolytes and electron donors synthesized in both leaves and roots demonstrate that osmoregulatory and electrical responses occur in these organs of P. maritimum under mild salt stress.

ACS Style

Simona Carfagna; Giovanna Salbitani; Michele Innangi; Bruno Menale; Olga De Castro; Catello Di Martino; Thomas Crawford. Simultaneous Biochemical and Physiological Responses of the Roots and Leaves of Pancratium maritimum (Amaryllidaceae) to Mild Salt Stress. Plants 2021, 10, 345 .

AMA Style

Simona Carfagna, Giovanna Salbitani, Michele Innangi, Bruno Menale, Olga De Castro, Catello Di Martino, Thomas Crawford. Simultaneous Biochemical and Physiological Responses of the Roots and Leaves of Pancratium maritimum (Amaryllidaceae) to Mild Salt Stress. Plants. 2021; 10 (2):345.

Chicago/Turabian Style

Simona Carfagna; Giovanna Salbitani; Michele Innangi; Bruno Menale; Olga De Castro; Catello Di Martino; Thomas Crawford. 2021. "Simultaneous Biochemical and Physiological Responses of the Roots and Leaves of Pancratium maritimum (Amaryllidaceae) to Mild Salt Stress." Plants 10, no. 2: 345.

Review
Published: 19 January 2021 in Sustainability
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In plant cells, ammonium is considered the most convenient nitrogen source for cell metabolism. However, despite ammonium being the preferred N form for microalgae, at higher concentrations, it can be toxic, and can cause growth inhibition. Microalgae’s tolerance to ammonium depends on the species, with various taxa showing different thresholds of tolerability and symptoms of toxicity. In the environment, ammonium at high concentrations represents a dangerous pollutant. It can affect water quality, causing numerous environmental problems, including eutrophication of downstream waters. For this reason, it is important to treat wastewater and remove nutrients before discharging it into rivers, lakes, or seas. A valid and sustainable alternative to conventional treatments could be provided by microalgae, coupling the nutrient removal from wastewater with the production of valuable biomass. This review is focused on ammonium and its importance in algal nutrition, but also on its problematic presence in aquatic systems such as wastewaters. The aim of this work is to provide recent information on the exploitation of microalgae in ammonium removal and the role of ammonium in microalgae metabolism.

ACS Style

Giovanna Salbitani; Simona Carfagna. Ammonium Utilization in Microalgae: A Sustainable Method for Wastewater Treatment. Sustainability 2021, 13, 956 .

AMA Style

Giovanna Salbitani, Simona Carfagna. Ammonium Utilization in Microalgae: A Sustainable Method for Wastewater Treatment. Sustainability. 2021; 13 (2):956.

Chicago/Turabian Style

Giovanna Salbitani; Simona Carfagna. 2021. "Ammonium Utilization in Microalgae: A Sustainable Method for Wastewater Treatment." Sustainability 13, no. 2: 956.

Journal article
Published: 29 June 2020 in Applied Sciences
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Bicarbonate ions are the primary source of inorganic carbon for autotrophic organisms living in aquatic environments. In the present study, we evaluated the shortterm (hours) effects of sodium bicarbonate (NaHCO3) addition on the growth and photosynthetic efficiency of the green algae Chlorella sorokiniana (211/8k). Bicarbonate was added to nonaxenic cultures at concentrations of 1, 2, and 3 g L-1 leading to a significant increase in biomass especially at the highest salt concentration (3 g L-1) and also showing a bactericidal and bacteriostatic effect that helped to keep a reduced microbial load in the algal culture. Furthermore, bicarbonate stimulated the increase in cellular content of chlorophyll a, improving the photosynthetic performance of cells. Since microalgae of genus Chlorella spp. show great industrial potential for the production of biofuels, nutraceuticals, cosmetics, health, and dietary supplements and the use of bicarbonate as a source of inorganic carbon led to shortterm responses in Chlorella sorokiniana, this method represents a valid alternative not only to the insufflation of carbon dioxide for the intensive cultures but also for the production of potentially bioactive compounds in a short period.

ACS Style

Giovanna Salbitani; Francesco Bolinesi; Mario Affuso; Federica Carraturo; Olga Mangoni; Simona Carfagna. Rapid and Positive Effect of Bicarbonate Addition on Growth and Photosynthetic Efficiency of The Green Microalgae Chlorella Sorokiniana (Chlorophyta, Trebouxiophyceae). Applied Sciences 2020, 10, 4515 .

AMA Style

Giovanna Salbitani, Francesco Bolinesi, Mario Affuso, Federica Carraturo, Olga Mangoni, Simona Carfagna. Rapid and Positive Effect of Bicarbonate Addition on Growth and Photosynthetic Efficiency of The Green Microalgae Chlorella Sorokiniana (Chlorophyta, Trebouxiophyceae). Applied Sciences. 2020; 10 (13):4515.

Chicago/Turabian Style

Giovanna Salbitani; Francesco Bolinesi; Mario Affuso; Federica Carraturo; Olga Mangoni; Simona Carfagna. 2020. "Rapid and Positive Effect of Bicarbonate Addition on Growth and Photosynthetic Efficiency of The Green Microalgae Chlorella Sorokiniana (Chlorophyta, Trebouxiophyceae)." Applied Sciences 10, no. 13: 4515.

Article
Published: 08 April 2020 in Journal of Plant Growth Regulation
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Despite being an autotrophic organism, Galdieria phlegrea (Galdieriaceae) has the ability to use glycerol thereby switching to heterotrophy in the dark and mixotrophy in the presence of light. To examine cellular changes during the switch to mixotrophic metabolism and finally to photoautotrophic metabolism, heterotrophic cells of G. phlegrea were exposed to light and split into two subcultures. Cells exposed only to light but cultivated in medium containing glycerol grew with a recovery time of at least 3 days. In a parallel culture, the simultaneous removal of glycerol from the culture medium and light exposure allowed Galdieria cells to rapidly recover their growth rate due to their ability to rapidly absorb ammonium from the medium. However, contrary to expectation, a higher content of total soluble protein was observed in light-exposed cells cultivated in medium containing glycerol compared to cells cultivated without glycerol. In addition, the level of Rubisco in cells exposed to light and cultivated without glycerol was higher than those in cells cultivated in medium containing glycerol, indicating full photosynthetic functionality after only 3 days of light treatment. The greater chlorophyll a content confirms that the photosynthetic activity of cells cultivated without glycerol recovers earlier than that of heterotrophic cells exposed to light but still cultivated in medium containing glycerol.

ACS Style

Giovanna Salbitani; Sabrina Cipolletta; Vincenza Vona; Catello Di Martino; Simona Carfagna. Heterotrophic Cultures of Galdieria phlegrea Shift to Autotrophy in the Presence or Absence of Glycerol. Journal of Plant Growth Regulation 2020, 40, 371 -378.

AMA Style

Giovanna Salbitani, Sabrina Cipolletta, Vincenza Vona, Catello Di Martino, Simona Carfagna. Heterotrophic Cultures of Galdieria phlegrea Shift to Autotrophy in the Presence or Absence of Glycerol. Journal of Plant Growth Regulation. 2020; 40 (1):371-378.

Chicago/Turabian Style

Giovanna Salbitani; Sabrina Cipolletta; Vincenza Vona; Catello Di Martino; Simona Carfagna. 2020. "Heterotrophic Cultures of Galdieria phlegrea Shift to Autotrophy in the Presence or Absence of Glycerol." Journal of Plant Growth Regulation 40, no. 1: 371-378.

Original article
Published: 01 January 2020 in Journal of Enzyme Inhibition and Medicinal Chemistry
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There is significant interest in increasing the microalgal efficiency for producing high-quality products that are commonly used as food additives in nutraceuticals. Some natural substances that can be extracted from algae include lipids, carbohydrates, proteins, carotenoids, long-chain polyunsaturated fatty acids, and vitamins. Generally, microalgal photoautotrophic growth can be maximised by optimising CO2 biofixation, and by adding sodium bicarbonate and specific bacteria to the microalgal culture. Recently, to enhance CO2 biofixation, a thermostable carbonic anhydrase (SspCA) encoded by the genome of the bacterium Sulfurihydrogenibium yellowstonense has been heterologously expressed and immobilised on the surfaces of bacteria. Carbonic anhydrases (CAs, EC 4.2.1.1) are ubiquitous metalloenzymes, which catalyse the physiologically reversible reaction of carbon dioxide hydration to bicarbonate and protons: CO2 + H2O ⇄ HCO3 − + H+. Herein, we demonstrate for the first time that the fragments of bacterial membranes containing immobilised SspCA (M-SspCA) on their surfaces can be doped into the microalgal culture of the green unicellular alga, Chlorella sorokiniana, to significantly enhance the biomass, photosynthetic activity, carotenoids production, and CA activity by this alga. These results are of biotechnological interest because C. sorokiniana is widely used in many different areas, including photosynthesis research, human pharmaceutical production, aquaculture-based food production, and wastewater treatment.

ACS Style

Giovanna Salbitani; Sonia Del Prete; Francesco Bolinesi; Olga Mangoni; Viviana De Luca; Vincenzo Carginale; William A. Donald; Claudiu T. Supuran; Simona Carfagna; Clemente Capasso. Use of an immobilised thermostable α-CA (SspCA) for enhancing the metabolic efficiency of the freshwater green microalga Chlorella sorokiniana. Journal of Enzyme Inhibition and Medicinal Chemistry 2020, 35, 913 -920.

AMA Style

Giovanna Salbitani, Sonia Del Prete, Francesco Bolinesi, Olga Mangoni, Viviana De Luca, Vincenzo Carginale, William A. Donald, Claudiu T. Supuran, Simona Carfagna, Clemente Capasso. Use of an immobilised thermostable α-CA (SspCA) for enhancing the metabolic efficiency of the freshwater green microalga Chlorella sorokiniana. Journal of Enzyme Inhibition and Medicinal Chemistry. 2020; 35 (1):913-920.

Chicago/Turabian Style

Giovanna Salbitani; Sonia Del Prete; Francesco Bolinesi; Olga Mangoni; Viviana De Luca; Vincenzo Carginale; William A. Donald; Claudiu T. Supuran; Simona Carfagna; Clemente Capasso. 2020. "Use of an immobilised thermostable α-CA (SspCA) for enhancing the metabolic efficiency of the freshwater green microalga Chlorella sorokiniana." Journal of Enzyme Inhibition and Medicinal Chemistry 35, no. 1: 913-920.

Journal article
Published: 01 January 2017 in BIO-PROTOCOL
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ACS Style

Giovanna Salbitani; Claudia Bottone; Simona Carfagna. Determination of Reduced and Total Glutathione Content in Extremophilic Microalga Galdieria phlegrea. BIO-PROTOCOL 2017, 7, 1 .

AMA Style

Giovanna Salbitani, Claudia Bottone, Simona Carfagna. Determination of Reduced and Total Glutathione Content in Extremophilic Microalga Galdieria phlegrea. BIO-PROTOCOL. 2017; 7 (13):1.

Chicago/Turabian Style

Giovanna Salbitani; Claudia Bottone; Simona Carfagna. 2017. "Determination of Reduced and Total Glutathione Content in Extremophilic Microalga Galdieria phlegrea." BIO-PROTOCOL 7, no. 13: 1.

Journal article
Published: 01 March 2016 in Journal of Nutritional Ecology and Food Research
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Galdieria sulphuraria was cultivated in a batch culture for around 20 days without CO2 addition to investigate contents in proteins and photosynthetic pigments. The analysis confirmed that the cells contained high amounts of pigments and in particular of phycocyanin (C-PC), a phycobiliprotein that represents the principal accessory pigment. C-PC is a blue pigment and for its excellent properties, is utilized in a number of applications. We extracted and partially purified the blue pigment C-PC from algal biomass in order to obtain its maximum content in the extracts. The extraction and the purification produced aqueous solutions of C-PC with concentrations around 2 mg mL–1 and with high purity with respect to total proteins. Furthermore, the C-PC extracted from the thermophilic microalgae Galdieria sulphuraria was thermostable. We propose the microalga Galdieria sulphuraria could be grown for the production of phycobiliproteins. The cultivation of the microalga Galdieria sulphuraria without CO2 supplement is also practical and economical.

ACS Style

Simona Carfagna; Giovanna Salbitani; Claudia Bottone; Vincenza Vona. Galdieria sulphuraria as a Possible Source of Food Colorant. Journal of Nutritional Ecology and Food Research 2016, 3, 67 -70.

AMA Style

Simona Carfagna, Giovanna Salbitani, Claudia Bottone, Vincenza Vona. Galdieria sulphuraria as a Possible Source of Food Colorant. Journal of Nutritional Ecology and Food Research. 2016; 3 (1):67-70.

Chicago/Turabian Style

Simona Carfagna; Giovanna Salbitani; Claudia Bottone; Vincenza Vona. 2016. "Galdieria sulphuraria as a Possible Source of Food Colorant." Journal of Nutritional Ecology and Food Research 3, no. 1: 67-70.

Journal article
Published: 02 February 2015 in Plant and Cell Physiology
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Sulfur deficiency in plant cells has not been considered as a potential abiotic factor that can induce oxidative stress. We studied the antioxidant defense system of Chlorella sorokiniana cultured under sulfur (S) deficiency, imposed for a maximum period of 24 h, to evaluate the effect of an S shortage on oxidative stress. S deprivation induced an immediate (30 min) but transient increase in the intracellular H2O2 content, which suggests that S limitation can lead to a temporary redox disturbance. After 24 h, S deficiency in Chlorella cells decreased the glutathione content to <10% of the value measured in cells that were not subjected to S deprivation. Consequently, we assumed that the cellular antioxidative mechanisms could be altered by a decrease in the total glutathione content. The total ascorbate pool increased within 2 h after the initiation of S depletion, and remained high until 6 h; however, ascorbate regeneration was inhibited under limited S conditions, indicated by a significant decrease in the ascorbate/dehydroascorbate (AsA/DHA) ratios. Furthermore, ascorbate peroxidase (APX) and superoxide dismutase (SOD) were activated under S deficiency, but we assumed that these enzymes were involved in maintaining the cellular H2O2 balance for at least 4 h after the initiation of S starvation. We concluded that S deprivation triggers redox changes and induces antioxidant enzyme activities in Chlorella cells. The accumulation of total ascorbate, changes in the reduced glutathione/oxidized glutathione (GSH/GSSG) ratios and an increase in the activity of SOD and APX enzymes indicate that oxidative perturbation occurs during S deprivation.

ACS Style

Giovanna Salbitani; Vincenza Vona; Claudia Bottone; Milena Petriccione; Simona Carfagna. Sulfur Deprivation Results in Oxidative Perturbation in Chlorella sorokiniana (211/8k). Plant and Cell Physiology 2015, 56, 897 -905.

AMA Style

Giovanna Salbitani, Vincenza Vona, Claudia Bottone, Milena Petriccione, Simona Carfagna. Sulfur Deprivation Results in Oxidative Perturbation in Chlorella sorokiniana (211/8k). Plant and Cell Physiology. 2015; 56 (5):897-905.

Chicago/Turabian Style

Giovanna Salbitani; Vincenza Vona; Claudia Bottone; Milena Petriccione; Simona Carfagna. 2015. "Sulfur Deprivation Results in Oxidative Perturbation in Chlorella sorokiniana (211/8k)." Plant and Cell Physiology 56, no. 5: 897-905.

Journal article
Published: 01 January 2015 in Natural Resources
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Nitrogen (N) and sulphur (S), being essential macronutrients, have important roles in microalgae metabolism. Effects of N- or S-shortage were investigated in the green microalgae Chlorella sorokiniana subjected to 24 h of starvation, by measuring the glutamine synthetase (GS) and O-ace- tylserine(thiol)lyase (OASTL) activities, proteins and amino acids levels. To test possible metabolic impact related to carbon (C) metabolism in response to N- or S-deprivation, starch and total C, N and S contents were also determined. The growth of C. sorokiniana cells was affected by N or S availability. The algae cultured for 24 h in a medium deprived of nitrogen or sulphur showed a decrease in the growth rate and changes in the average volume cell. Nitrogen starvation affected proteins level in the algae cells more than S-deprivation did. The decline in the protein levels observed under S-deficient conditions was coupled with the accumulation of the amide glutamine and with OASTL activity increase; additionally, N-deficiency promoted a decrease in cysteine (Cys) levels (50%) and an increase in GS activity. Nevertheless, S-deprivation had negligible effects on GS activity, while N-deprivation significantly affected OASTL activity. Total C was also estimated in cells N- or S-deprived; nitrogen deprivation strongly affected total C content more than S-deprivation, which in addition reduced the content of C and N, but leaves intact their ratios. Our results support the hypothesis that in Chlorella sorokiniana cells a reciprocal influence of N, S and C assimilation occurs.

ACS Style

Simona Carfagna; Giovanna Salbitani; Claudia Bottone; Anna De Marco; Vincenza Vona. Cross-Effects of Nitrogen and Sulphur Starvation in Chlorella sorokiniana 211/8K. Natural Resources 2015, 06, 221 -229.

AMA Style

Simona Carfagna, Giovanna Salbitani, Claudia Bottone, Anna De Marco, Vincenza Vona. Cross-Effects of Nitrogen and Sulphur Starvation in Chlorella sorokiniana 211/8K. Natural Resources. 2015; 06 (04):221-229.

Chicago/Turabian Style

Simona Carfagna; Giovanna Salbitani; Claudia Bottone; Anna De Marco; Vincenza Vona. 2015. "Cross-Effects of Nitrogen and Sulphur Starvation in Chlorella sorokiniana 211/8K." Natural Resources 06, no. 04: 221-229.

Communication
Published: 04 August 2014 in Metabolites
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In the unicellular green alga Chlorella sorokiniana (211/8 k), the protein O-acetylserine(thiol)lyase (OASTL), representing the key-enzyme in the biosynthetic cysteine pathway, was isolated and purified to apparent homogeneity. The purification was carried out in cells grown in the presence of all nutrients or in sulphate (S) deprived cells. After 24 h of S-starvation, a 17-fold increase in the specific activity of OASTL was measured. In order to enable the identification of OASTL proteins from non-model organisms such as C. sorokiniana, the recombinant his-tagged SAT5 protein from Arabidopsis thaliana was immobilized by metal chelate chromatography. OASTL proteins from C. sorokiniana were affinity purified in one step and activities were enhanced 29- and 41-fold, from S-sufficient and S-starved (24 h) cells, respectively. The successful application of SAT/OASTL interaction for purification confirms for the first time the existence of the cysteine synthase complexes in microalgae. The purified proteins have apparent molecular masses between 32–34 kDa and are thus slightly larger compared to those found in Arabidopsis thaliana and other vascular plants. The enhanced OASTL activity in S-starved cells can be attributed to increased amounts of plastidic and the emergence of cytosolic OASTL isoforms. The results provide proof-of-concept for the biochemical analysis of the cysteine synthase complex in diverse microalgal species.

ACS Style

Giovanna Salbitani; Markus Wirtz; Rüdiger Hell; Simona Carfagna. Affinity Purification of O-Acetylserine(thiol)lyase from Chlorella sorokiniana by Recombinant Proteins from Arabidopsis thaliana. Metabolites 2014, 4, 629 -639.

AMA Style

Giovanna Salbitani, Markus Wirtz, Rüdiger Hell, Simona Carfagna. Affinity Purification of O-Acetylserine(thiol)lyase from Chlorella sorokiniana by Recombinant Proteins from Arabidopsis thaliana. Metabolites. 2014; 4 (3):629-639.

Chicago/Turabian Style

Giovanna Salbitani; Markus Wirtz; Rüdiger Hell; Simona Carfagna. 2014. "Affinity Purification of O-Acetylserine(thiol)lyase from Chlorella sorokiniana by Recombinant Proteins from Arabidopsis thaliana." Metabolites 4, no. 3: 629-639.

Journal article
Published: 08 April 2013 in SpringerPlus
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The heavy metal pollution in soils and aquatic environments is a serious ecological problem. In the green-microalga Chlorella sorokiniana 211-8K (Chlorophyceae) exposed to ions of lead (Pb) and cadmium (Cd) we studied the metabolic responses to the toxicity of these two heavy metals. Our data indicate that both the pollutants alter the alga cell ultrastructure and its physiological characteristics (growth, photosynthesis, respiration, enzyme activities). The toxic effects of the two metals resulted time-dependent to the exposure. After 24 h of treatment with 250 μM Pb or Cd, photosynthesis was inhibited until to 77 and 86%, however respiration was strongly enhanced up to 300 and 350%, respectively. In the algal cells Pb or Cd exposure induced a reduction in the content of the total chlorophylls and a decrease of the soluble protein levels, significantly compromising the growth, particularly in cultures cadmium-treated. We report data on ultrastructural changes induced by the two heavy metals; they affected overall chloroplast ultrastructure of the alga. Most importantly, the O-acetyl-L-serine(thiol)lyase (OASTL) activity was appreciably increased after only 2 h of Cd exposure, indicating the existence of a link between the metal contamination and cysteine synthesis. Then, Chlorella sorokiniana cells seem to better tolerate high concentrations of Pb while appear to be more sensitive to Cd ions. These results provide some additional information that can lead to better understand consequences of heavy metal poisoning in microalgae.

ACS Style

Simona Carfagna; Nicola Lanza; Giovanna Salbitani; Adriana Basile; Sergio Sorbo; Vincenza Vona. Physiological and morphological responses of Lead or Cadmium exposed Chlorella sorokiniana 211-8K (Chlorophyceae). SpringerPlus 2013, 2, 1 -7.

AMA Style

Simona Carfagna, Nicola Lanza, Giovanna Salbitani, Adriana Basile, Sergio Sorbo, Vincenza Vona. Physiological and morphological responses of Lead or Cadmium exposed Chlorella sorokiniana 211-8K (Chlorophyceae). SpringerPlus. 2013; 2 (1):1-7.

Chicago/Turabian Style

Simona Carfagna; Nicola Lanza; Giovanna Salbitani; Adriana Basile; Sergio Sorbo; Vincenza Vona. 2013. "Physiological and morphological responses of Lead or Cadmium exposed Chlorella sorokiniana 211-8K (Chlorophyceae)." SpringerPlus 2, no. 1: 1-7.

Journal article
Published: 15 December 2011 in Journal of Plant Physiology
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We analyzed the effects of deprivation and subsequent restoration of sulphate (S) in the nutrient solution on cysteine (Cys) and O-acetyl-L-serine (OAS) levels in Chlorella sorokiniana (211/8k). The removal of S from the culture medium caused a time-dependent increase in O-acetyl-L-serine(thiol)lyase (OASTL) activity and a decrease in soluble proteins content. The protein gel blot analysis was used to show that OASTL isoforms are located in the chloroplast and in the cytoplasm of S-starved cells. S-deprivation caused a decrease in the intracellular levels of Cys and glutathione (GSH) and an increase in serine (Ser) and OAS, reflecting an imbalance between sulphur and nitrogen assimilation. Re-supplying of sulphate to S-starved cells produced a decrease in OAS levels and concomitant rapid increase in Cys and GSH concentrations. The simultaneous addition of OAS and sulphate to S-starved cells did not further increase the concentration of Cys, suggesting the existence of a threshold level of intracellular Cys that is independent of the cellular concentration of OAS. Our findings that OAS is stored during S-starvation and that its quick decrease appears to be coupled with the increase of Cys levels upon re-supply of sulphate, imply that the central role that these two compounds play is in the regulation of sulphur-assimilating enzymes in response to the S status of the cell.

ACS Style

Simona Carfagna; Giovanna Salbitani; Vincenza Vona; Sergio Esposito. Changes in cysteine and O-acetyl-l-serine levels in the microalga Chlorella sorokiniana in response to the S-nutritional status. Journal of Plant Physiology 2011, 168, 2188 -2195.

AMA Style

Simona Carfagna, Giovanna Salbitani, Vincenza Vona, Sergio Esposito. Changes in cysteine and O-acetyl-l-serine levels in the microalga Chlorella sorokiniana in response to the S-nutritional status. Journal of Plant Physiology. 2011; 168 (18):2188-2195.

Chicago/Turabian Style

Simona Carfagna; Giovanna Salbitani; Vincenza Vona; Sergio Esposito. 2011. "Changes in cysteine and O-acetyl-l-serine levels in the microalga Chlorella sorokiniana in response to the S-nutritional status." Journal of Plant Physiology 168, no. 18: 2188-2195.

Journal article
Published: 01 April 2011 in Environmental and Experimental Botany
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The mixed effects of nitrogen nutrition and sulphate assimilation were investigated in barley plants (Hordeum vulgare var. Alfeo) that were subjected to long-term sulphur and/or nitrogen starvation, by measuring the O-acetylserine(thio)lyase (OASTL-EC 4.2.99.8) activity, changes in -SH compounds and amino acid levels. The growth of barley plants cultured in the hydroponic vessels was severely affected by altered nutrient levels. The barley plants grown in medium deprived of nitrogen and/or sulphur sources for 21 days showed increase in both root length and weight. In contrast, the shoot growth was reduced in nitrogen-starved plants and was unaffected by sulphur deprivation. Sulphur starvation affected the level of proteins in barley plants more than nitrogen deprivation. The decline in the protein levels observed under sulphur-deficient conditions was coupled with the accumulation of glutamine, asparagine and serine, mainly in the roots; additionally, a nitrogen deficiency in the roots promoted a decrease in both glutathione and cysteine levels

ACS Style

Simona Carfagna; Vincenza Vona; Vittoria Di Martino; Sergio Esposito; Carmelo Rigano. Nitrogen assimilation and cysteine biosynthesis in barley: Evidence for root sulphur assimilation upon recovery from N deprivation. Environmental and Experimental Botany 2011, 71, 18 -24.

AMA Style

Simona Carfagna, Vincenza Vona, Vittoria Di Martino, Sergio Esposito, Carmelo Rigano. Nitrogen assimilation and cysteine biosynthesis in barley: Evidence for root sulphur assimilation upon recovery from N deprivation. Environmental and Experimental Botany. 2011; 71 (1):18-24.

Chicago/Turabian Style

Simona Carfagna; Vincenza Vona; Vittoria Di Martino; Sergio Esposito; Carmelo Rigano. 2011. "Nitrogen assimilation and cysteine biosynthesis in barley: Evidence for root sulphur assimilation upon recovery from N deprivation." Environmental and Experimental Botany 71, no. 1: 18-24.

Journal article
Published: 28 February 2010 in Aquaculture
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Unicellular algae represent an interesting source of bioactive food ingredients. In this study, fatty acids and\ud carotenoids of Koliella antarctica, a psychrophylic Antarctic unicellular alga, were investigated. K. antarctica\ud was cultivated at different temperatures and harvested at the early exponential growth phase and at the late\ud exponential growth phase. After 240 h, at the end of the late exponential growth phase, the cell biomass\ud concentration was 1.1 g L−1 at 10 °C while it was 2.2 g L−1 at 15 °C. The lipid profile of K. antarctica was rich\ud in polyunsaturated fatty acids (PUFA) particularly at the early exponential phase (50.8% of total fatty acids).\ud The comparison of data obtained from algae cultivated at 10 °C and 15 °C, showed at 15 °C a strong increase\ud in saturated lipids and a decrease in PUFA. At the same time the presence of EPA and DHA was marginally\ud affected, with a percentage decrease around 15–20%. The productivity of EPA and DHA was similar at the two\ud growth temperatures with maximum values of 0.6 mg L−1 day−1 and 1.3 mg L−1 day−1, at 10 and 15 °C,\ud respectively.\ud In K. antarctica cultures, the concentration of lutein and astaxanthin increased during growth up to 1.4 g per\ud 100 g dry weight for both compounds. This is one of the highest concentrations reported in the literature for\ud carotenoid production by unicellular algae, with a total carotenoid productivity of 3.1 mg L−1 day−1.\ud Although optimization studies to increase K. antarctica biomass production were not yet carried out, data\ud suggested that this alga is a promising source for low cost production of valuable bioactive compounds. The\ud performance recorded at 15 °C suggested that it could be particularly suitable for outdoor cultivation during\ud the winter season in the Mediterranean region

ACS Style

Vincenzo Fogliano; Carlo Andreoli; Anna Martello; Marianna Caiazzo; Ornella Lobosco; Fabio Formisano; Pier Antimo Carlino; Giuseppe Meca; Giulia Graziani; Vittoria Di Martino Rigano; Vincenza Vona; Simona Carfagna; Carmelo Rigano. Functional ingredients produced by culture of Koliella antarctica. Aquaculture 2010, 299, 115 -120.

AMA Style

Vincenzo Fogliano, Carlo Andreoli, Anna Martello, Marianna Caiazzo, Ornella Lobosco, Fabio Formisano, Pier Antimo Carlino, Giuseppe Meca, Giulia Graziani, Vittoria Di Martino Rigano, Vincenza Vona, Simona Carfagna, Carmelo Rigano. Functional ingredients produced by culture of Koliella antarctica. Aquaculture. 2010; 299 (1-4):115-120.

Chicago/Turabian Style

Vincenzo Fogliano; Carlo Andreoli; Anna Martello; Marianna Caiazzo; Ornella Lobosco; Fabio Formisano; Pier Antimo Carlino; Giuseppe Meca; Giulia Graziani; Vittoria Di Martino Rigano; Vincenza Vona; Simona Carfagna; Carmelo Rigano. 2010. "Functional ingredients produced by culture of Koliella antarctica." Aquaculture 299, no. 1-4: 115-120.

Comparative study
Published: 01 July 2006 in Plant, Cell & Environment
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Temperature responses of nitrate reductase (NR) were studied in the psychrophilic unicellular alga, Koliella antarctica, and in the mesophilic species, Chlorella sorokiniana. Enzymes from both species were purified to near homogeneity by Blue Sepharose (Pharmacia, Uppsala, Sweden) affinity chromatography and high‐resolution anion‐exchange chromatography (MonoQ; Pharmacia; Uppsala, Sweden). Both enzymes have a subunit molecular mass of 100 kDa, and K. antarctica NR has a native molecular mass of 367 kDa. NR from K. antarctica used both NADPH and NADH, whereas NR from C. sorokiniana used NADH only. Both NRs used reduced methyl viologen (MVH) or benzyl viologen (BVH). In crude extracts, maximal NADH and MVH‐dependent activities of cryophilic NR were found at 15 and 35 °C, respectively, and retained 77 and 62% of maximal activity, respectively, at 10 °C. Maximal NADH and MVH‐dependent activities of mesophilic NR, however, were found at 25 and 45 °C, respectively, with only 33 and 23% of maximal activities being retained at 10 °C. In presence of 2 µm flavin adenine dinucleotide (FAD), activities of cryophilic NADH:NR and mesophilic NADH:NR were stable up to 25 and 35 °C, respectively. Arrhenius plots constructed with cryophilic and mesophilic MVH:NR rate constants, in both presence or absence of FAD, showed break points at 15 and 25 °C, respectively. Essentially, similar results were obtained for purified enzymes and for activities measured in crude extracts. Factors by which the rate increases by raising temperature 10 °C (Q10) and apparent activation energy (Ea) values for NADH and MVH activities measured in enzyme preparations without added FAD differed slightly from those measured with FAD. Overall thermal features of the NADH and MVH activities of the cryophilic NR, including optimal temperatures, heat inactivation (with/without added FAD) and break‐point temperature in Arrhenius plots, are all shifted by about 10 °C towards lower temperatures than those of the mesophilic enzyme. Transfer of electrons from NADH to nitrate occurs via all three redox centres within NR molecule, whereas transfer from MVH requires Mo‐pterin prosthetic group only; therefore, our results strongly suggest that structural modification(s) for cold adaptation affect thermodynamic properties of each of the functional domains within NR holoenzyme in equal measure.

ACS Style

Vittoria Di Martino Rigano; Vincenza Vona; Ornella Lobosco; Petronia Carillo; John E. Lunn; Simona Carfagna; Sergio Esposito; Marianna Caiazzo; Carmelo Rigano. Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana. Plant, Cell & Environment 2006, 29, 1400 -1409.

AMA Style

Vittoria Di Martino Rigano, Vincenza Vona, Ornella Lobosco, Petronia Carillo, John E. Lunn, Simona Carfagna, Sergio Esposito, Marianna Caiazzo, Carmelo Rigano. Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana. Plant, Cell & Environment. 2006; 29 (7):1400-1409.

Chicago/Turabian Style

Vittoria Di Martino Rigano; Vincenza Vona; Ornella Lobosco; Petronia Carillo; John E. Lunn; Simona Carfagna; Sergio Esposito; Marianna Caiazzo; Carmelo Rigano. 2006. "Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana." Plant, Cell & Environment 29, no. 7: 1400-1409.

Journal article
Published: 01 February 2003 in Planta
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Evidence is provided for a close link between glutamate (Glu) synthesis and the production of reducing power by the oxidative pentose phosphate pathway (OPPP) in barley ( Hordeum vulgare L. var. Alfeo) root plastids. A rapid procedure for isolating organelles gave yields of plastids of over 30%, 60% of which were intact. The formation of Glu by intact plastids fed with glutamine and 2-oxoglutarate, both substrates of glutamate synthase (GOGAT), depends on glucose-6-phosphate (Glc-6-P) supply. The whole process exhibited an apparent K(m Glc-6-P) of 0.45 mM and is abolished by azaserine, a specific inhibitor of GOGAT; ATP caused a decrease in the rate of Glu formation. Glucose and other sugar phosphates were not as effective in supporting Glu synthesis with respect to Glc-6-P; only ribose-5-phosphate, an intermediate of OPPP, supported rates equivalent to Glc-6-P. Glucose-6-phosphate dehydrogenase (Glc6PDH) rapidly purified from root plastids showed an apparent K(m Glc-6-P) of 0.96 mM and an apparent K(m NADP)(+) of 9 micro M. The enzyme demonstrated high tolerance to NADPH, exhibiting a K(i) (NADPH) of 58.6 micro M and selectively reacted with antibodies against potato plastidic, but not chloroplastic, Glc6PDH isoform. The data support the hypothesis that plastidic OPPP is the main site of reducing power supply for GOGAT within the plastids, and suggest that the plastidic OPPP would be able to sustain Glu synthesis under high NADPH:NADP(+) ratios even if the plastidic Glc6PDH may not be functioning at its highest rates.

ACS Style

Sergio Esposito; Graziella Massaro; Vincenza Vona; Vittoria Di Martino Rigano; Simona Carfagna. Glutamate synthesis in barley roots: the role of the plastidic glucose-6-phosphate dehydrogenase. Planta 2003, 216, 639 -647.

AMA Style

Sergio Esposito, Graziella Massaro, Vincenza Vona, Vittoria Di Martino Rigano, Simona Carfagna. Glutamate synthesis in barley roots: the role of the plastidic glucose-6-phosphate dehydrogenase. Planta. 2003; 216 (4):639-647.

Chicago/Turabian Style

Sergio Esposito; Graziella Massaro; Vincenza Vona; Vittoria Di Martino Rigano; Simona Carfagna. 2003. "Glutamate synthesis in barley roots: the role of the plastidic glucose-6-phosphate dehydrogenase." Planta 216, no. 4: 639-647.

Journal article
Published: 01 January 2000 in Functional Plant Biology
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Chlorella sorokinianaShihira & Krauss, strain 211/8K resuspended in a illuminated mediumshowed continuous growth, and concomitantly NH4 +in the medium depleted at a constant rate. Upon sulfate removal, i) growthdeclined, ceasing within 5 h; ii) NH4 + depletionbecame almost undetectable over 2 h; and iii) photosynthetic capacity (Pc) wasreduced over 24 h by 80% in the light, but was reduced by only30% in darkness. Over 24 h of S starvation the chlorophyll content ofilluminated cells decreased by 50%, whereas that of darkened cellsdecreased by only 10%. Sulfate-deprivation over 24 h resulted in anoticeable increase in the starch content of the cell and a net increase inthe pools of glutamate, glutamine, serine and asparagine. Cysteine content, incontrast, was decreased. Sulfate addition to cells starved of S for 24 hprovoked a sudden time-dependent increase in Pc and in an immediate renewal ofgrowth in light but not in darkness. Sulphate supply also caused a suddenenhancement of respiratory oxygen consumption and a prompt degradation ofstarch. Starch was degraded at a higher rate in illuminated than in darkenedcells. After the S addition, depletion of NH4 + inthe medium occurred at slowly increasing rates; amino acids decreasednoticeably over 4 h, where in contrast, cysteine increased noticeably.

ACS Style

Vittoria Di Martino Rigano; Vincenza Vona; Simona Carfagna; Sergio Esposito; Petronia Carillo; Carmelo Rigano. Effects of sulfate-starvation and re-supply on growth, NH4+ uptake and starch metabolism in Chlorella sorokiniana. Functional Plant Biology 2000, 27, 335 -342.

AMA Style

Vittoria Di Martino Rigano, Vincenza Vona, Simona Carfagna, Sergio Esposito, Petronia Carillo, Carmelo Rigano. Effects of sulfate-starvation and re-supply on growth, NH4+ uptake and starch metabolism in Chlorella sorokiniana. Functional Plant Biology. 2000; 27 (4):335-342.

Chicago/Turabian Style

Vittoria Di Martino Rigano; Vincenza Vona; Simona Carfagna; Sergio Esposito; Petronia Carillo; Carmelo Rigano. 2000. "Effects of sulfate-starvation and re-supply on growth, NH4+ uptake and starch metabolism in Chlorella sorokiniana." Functional Plant Biology 27, no. 4: 335-342.

Journal article
Published: 01 February 1999 in Physiologia Plantarum
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Vincenza Vona; Vittoria Di Martino Rigano; Sergio Esposito; Petronia Carillo; Simona Carfagna; Carmelo Rigano. Growth, photosynthesis, and respiration of Chlorella sorokiniana after N-starvation. Interactions between light, CO 2 and NH 4+ supply. Physiologia Plantarum 1999, 105, 288 -293.

AMA Style

Vincenza Vona, Vittoria Di Martino Rigano, Sergio Esposito, Petronia Carillo, Simona Carfagna, Carmelo Rigano. Growth, photosynthesis, and respiration of Chlorella sorokiniana after N-starvation. Interactions between light, CO 2 and NH 4+ supply. Physiologia Plantarum. 1999; 105 (2):288-293.

Chicago/Turabian Style

Vincenza Vona; Vittoria Di Martino Rigano; Sergio Esposito; Petronia Carillo; Simona Carfagna; Carmelo Rigano. 1999. "Growth, photosynthesis, and respiration of Chlorella sorokiniana after N-starvation. Interactions between light, CO 2 and NH 4+ supply." Physiologia Plantarum 105, no. 2: 288-293.

Journal article
Published: 01 January 1998 in Journal of Plant Physiology
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Sergio Esposito; Petronia Carillo; Simona Carfagna. Ammonium metabolism stimulation of glucose-6P dehydrogenase and phosphoenolpyruvate carboxylase in young barley roots. Journal of Plant Physiology 1998, 153, 61 -66.

AMA Style

Sergio Esposito, Petronia Carillo, Simona Carfagna. Ammonium metabolism stimulation of glucose-6P dehydrogenase and phosphoenolpyruvate carboxylase in young barley roots. Journal of Plant Physiology. 1998; 153 (1-2):61-66.

Chicago/Turabian Style

Sergio Esposito; Petronia Carillo; Simona Carfagna. 1998. "Ammonium metabolism stimulation of glucose-6P dehydrogenase and phosphoenolpyruvate carboxylase in young barley roots." Journal of Plant Physiology 153, no. 1-2: 61-66.

Journal article
Published: 01 January 1995 in Giornale botanico italiano
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Vittoria Di Martino Rigano; Simona Carfagna; Vincenza Vona; Petronia Carillo; Sergio Esposito; Carmelo Rigano. Effect of the light on ammonium assimilation by roots of young barley plants. Giornale botanico italiano 1995, 129, 943 -944.

AMA Style

Vittoria Di Martino Rigano, Simona Carfagna, Vincenza Vona, Petronia Carillo, Sergio Esposito, Carmelo Rigano. Effect of the light on ammonium assimilation by roots of young barley plants. Giornale botanico italiano. 1995; 129 (4):943-944.

Chicago/Turabian Style

Vittoria Di Martino Rigano; Simona Carfagna; Vincenza Vona; Petronia Carillo; Sergio Esposito; Carmelo Rigano. 1995. "Effect of the light on ammonium assimilation by roots of young barley plants." Giornale botanico italiano 129, no. 4: 943-944.