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Dr. Sushanta Kumar Saha
Shannon Applied Biotechnology Centre, Limerick Institute of Technology

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0 Astaxanthin
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0 beta-carotene

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Journal article
Published: 16 January 2021 in Heliyon
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Marine diatoms are a potential source for lipids and carbohydrates, which can have several applications ranging from biofuels to nutraceuticals. Due to their siliceous cellular structure and the complex nature of different lipid classes, it is important to understand the effect of biomass pre-treatment on the extractability of marine diatom lipids. In the present study, we tested the effect of four biomass pre-treatments (acid, base, anionic detergent, and non-ionic detergent) conditions on the extractability of lipids from Amphora sp. biomass. Lipids were extracted under identical supercritical fluid extraction (SFE) conditions from each of the above mentioned pre-treated biomass of Amphora sp. grown with or without silica. The fatty acids profile of saponified lipids was analysed by LC-MS. Results obtained in this study suggest each pre-treatment has a specific effect on the fatty acids profile. Therefore, depending on the downstream application of lipids (biodiesel or nutritional), both types of biomass and their pre-treatment conditions need to be considered. From the fermentation study for biomass evaluation as bioethanol feedstock, it was found that the complex carbohydrates of Amphora sp. biomass were easily convertible by autoclaving to monomer sugars, which were suitable for bioethanol production by yeast fermentation.

ACS Style

Paul Hogan; Paz Otero; Patrick Murray; Sushanta Kumar Saha. Effect of biomass pre-treatment on supercritical CO2 extraction of lipids from marine diatom Amphora sp. and its biomass evaluation as bioethanol feedstock. Heliyon 2021, 7, e05995 .

AMA Style

Paul Hogan, Paz Otero, Patrick Murray, Sushanta Kumar Saha. Effect of biomass pre-treatment on supercritical CO2 extraction of lipids from marine diatom Amphora sp. and its biomass evaluation as bioethanol feedstock. Heliyon. 2021; 7 (1):e05995.

Chicago/Turabian Style

Paul Hogan; Paz Otero; Patrick Murray; Sushanta Kumar Saha. 2021. "Effect of biomass pre-treatment on supercritical CO2 extraction of lipids from marine diatom Amphora sp. and its biomass evaluation as bioethanol feedstock." Heliyon 7, no. 1: e05995.

Journal article
Published: 10 January 2021 in Marine Drugs
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Microalgae are at the start of the food chain, and many are known producers of a significant amount of lipids with essential fatty acids. However, the bioactivity of microalgal lipids for anti-inflammatory and antithrombotic activities have rarely been investigated. Therefore, for a sustainable source of the above bioactive lipids, the present study was undertaken. The total lipids of microalga Chlorococcum sp., isolated from the Irish coast, were fractionated into neutral-, glyco-, and phospho-lipids, and were tested in vitro for their anti-inflammatory and antithrombotic activities. All tested lipid fractions showed strong anti-platelet-activating factor (PAF) and antithrombin activities in human platelets (half maximal inhibitory concentration (IC50) values ranging ~25–200 μg of lipid) with the highest activities in glyco- and phospho-lipid fractions. The structural analysis of the bioactive lipid fraction-2 revealed the presence of specific sulfoquinovosyl diacylglycerols (SQDG) bioactive molecules and the HexCer-t36:2 (t18:1/18:1 and 18:2/18:0) cerebrosides with a phytosphingosine (4-hydrosphinganine) base, while fraction-3 contained bioactive phosphatidylcholine (PC) and phosphatidylethanolamine (PE) molecules. These novel bioactive lipids of Chlorococcum sp. with putative health benefits may indicate that marine microalgae can be a sustainable alternative source for bioactive lipids production for food supplements and nutraceutical applications. However, further studies are required towards the commercial technology pathways development and biosafety analysis for the use of the microalga.

ACS Style

Katie Shiels; Alexandros Tsoupras; Ronan Lordan; Constantina Nasopoulou; Ioannis Zabetakis; Patrick Murray; Sushanta Kumar Saha. Bioactive Lipids of Marine Microalga Chlorococcum sp. SABC 012504 with Anti-Inflammatory and Anti-thrombotic Activities. Marine Drugs 2021, 19, 28 .

AMA Style

Katie Shiels, Alexandros Tsoupras, Ronan Lordan, Constantina Nasopoulou, Ioannis Zabetakis, Patrick Murray, Sushanta Kumar Saha. Bioactive Lipids of Marine Microalga Chlorococcum sp. SABC 012504 with Anti-Inflammatory and Anti-thrombotic Activities. Marine Drugs. 2021; 19 (1):28.

Chicago/Turabian Style

Katie Shiels; Alexandros Tsoupras; Ronan Lordan; Constantina Nasopoulou; Ioannis Zabetakis; Patrick Murray; Sushanta Kumar Saha. 2021. "Bioactive Lipids of Marine Microalga Chlorococcum sp. SABC 012504 with Anti-Inflammatory and Anti-thrombotic Activities." Marine Drugs 19, no. 1: 28.

Journal article
Published: 28 December 2020 in Current Research in Green and Sustainable Chemistry
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An integrated approach on uranium adsorption and emulsification of oils was evaluated using extracellular polysaccharides (EPS) of a marine unicellular cyanobacterium Synechococcus elongatus BDU130911. EPS gel of S. elongatus BDU130911 was able to adsorb uranium at the rate of 75% per gram dry weight. Uranium follows a monolayer adsorption onto EPS gel surface as revealed by Langmuir isotherm. Energy-dispersive X-ray fluorescence (EDXRF) analysis and powder X-ray diffraction analysis further confirms the uranium adsorption to the EPS gel of S. elongatus BDU130911. The culture filtrate of S. elongatus BDU130911 exhibited biosurfactant property and formed a stable emulsion with petrol (EI24 51.2%) due to the presence of uronic acid and rhamnose sugar. These findings suggest that the EPS of S. elongatus BDU130911 biomass has the potential to be used as a green adsorbing agent for the effective extraction of radionucleotide and petroleum hydrocarbons.

ACS Style

Vijayaragavan Rashmi; Arulraj Darshana; Thangaraj Bhuvaneshwari; Sushanta Kumar Saha; Lakshmanan Uma; Dharmar Prabaharan. Uranium adsorption and oil emulsification by extracellular polysaccharide (EPS) of a halophilic unicellular marine cyanobacterium Synechococcus elongatus BDU130911. Current Research in Green and Sustainable Chemistry 2020, 4, 100051 .

AMA Style

Vijayaragavan Rashmi, Arulraj Darshana, Thangaraj Bhuvaneshwari, Sushanta Kumar Saha, Lakshmanan Uma, Dharmar Prabaharan. Uranium adsorption and oil emulsification by extracellular polysaccharide (EPS) of a halophilic unicellular marine cyanobacterium Synechococcus elongatus BDU130911. Current Research in Green and Sustainable Chemistry. 2020; 4 ():100051.

Chicago/Turabian Style

Vijayaragavan Rashmi; Arulraj Darshana; Thangaraj Bhuvaneshwari; Sushanta Kumar Saha; Lakshmanan Uma; Dharmar Prabaharan. 2020. "Uranium adsorption and oil emulsification by extracellular polysaccharide (EPS) of a halophilic unicellular marine cyanobacterium Synechococcus elongatus BDU130911." Current Research in Green and Sustainable Chemistry 4, no. : 100051.

Review
Published: 16 September 2020 in Applied Sciences
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Lutein is particularly known to help maintain normal visual function by absorbing and attenuating the blue light that strikes the retina in our eyes. The effect of overexposure to blue light on our eyes due to the excessive use of electronic devices is becoming an issue of modern society due to insufficient dietary lutein consumption through our normal diet. There has, therefore, been an increasing demand for lutein-containing dietary supplements and also in the food industry for lutein supplementation in bakery products, infant formulas, dairy products, carbonated drinks, energy drinks, and juice concentrates. Although synthetic carotenoid dominates the market, there is a need for environmentally sustainable carotenoids including lutein production pathways to match increasing consumer demand for natural alternatives. Currently, marigold flowers are the predominant natural source of lutein. Microalgae can be a competitive sustainable alternative, which have higher growth rates and do not require arable land and/or a growth season. Currently, there is no commercial production of lutein from microalgae, even though astaxanthin and β-carotene are commercially produced from specific microalgal strains. This review discusses the potential microalgae strains for commercial lutein production, appropriate cultivation strategies, and the challenges associated with realising a commercial market share.

ACS Style

Sushanta Kumar Saha; Hande Ermis; Patrick Murray. Marine Microalgae for Potential Lutein Production. Applied Sciences 2020, 10, 6457 .

AMA Style

Sushanta Kumar Saha, Hande Ermis, Patrick Murray. Marine Microalgae for Potential Lutein Production. Applied Sciences. 2020; 10 (18):6457.

Chicago/Turabian Style

Sushanta Kumar Saha; Hande Ermis; Patrick Murray. 2020. "Marine Microalgae for Potential Lutein Production." Applied Sciences 10, no. 18: 6457.

Journal article
Published: 18 July 2020 in Biomolecules
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The structures of bioactive polar lipids (PLs) of Irish ale with potent antithrombotic and cardioprotective properties were elucidated. Ale PL was fractionated by preparative thin layer chromatography (TLC) into subclasses, and their antithrombotic effect was assessed against human platelet aggregation induced by the pro-inflammatory mediator, platelet-activating factor (PAF). The fatty acid content and the overall structures of ale PL were elucidated by liquid chromatography mass spectrometry (LC-MS). Phosphatidylcholines (PC) and molecules of the sphingomyelin (SM) family exhibited the strongest anti-PAF effects, followed by phosphatidylethanolamines (PE). PC contained higher amounts of omega-3 polyunsaturated fatty acids (n-3 PUFA) and thus the lowest n-6/n-3 ratio. Bioactive diacyl and alkyl-acyl PC and PE molecules bearing n-3 PUFA at their sn-2 position, especially docosahexaenoic acid (DHA) and α-linolenic acid (ALA) but mostly oleic acid (OA), were identified in both PC and PE subclasses. Eicosapentaenoic acid (EPA) was present only in bioactive PC molecules and not in PE, explaining the lower anti-PAF effects of PE. Bioactive sphingolipid and glycolipid molecules with reported anti-inflammatory and anti-tumour properties, such as specific ceramides and glucosylcerebrosides with sphingosine, phytosphingosine and dihydrosphingosine bases but also specific monogalactodiglycerides and SM species bearing ALA at their sn-2 position, were identified in the SM subclass, providing a rational for its strong bioactivities against the PAF pathway. Further studies are required on the health benefits of bioactive PL from beer and brewery by-products.

ACS Style

Alexandros Tsoupras; Ronan Lordan; Eoin O'keefe; Katie Shiels; Sushanta Kumar Saha; Ioannis Zabetakis. Structural Elucidation of Irish Ale Bioactive Polar Lipids with Antithrombotic Properties. Biomolecules 2020, 10, 1075 .

AMA Style

Alexandros Tsoupras, Ronan Lordan, Eoin O'keefe, Katie Shiels, Sushanta Kumar Saha, Ioannis Zabetakis. Structural Elucidation of Irish Ale Bioactive Polar Lipids with Antithrombotic Properties. Biomolecules. 2020; 10 (7):1075.

Chicago/Turabian Style

Alexandros Tsoupras; Ronan Lordan; Eoin O'keefe; Katie Shiels; Sushanta Kumar Saha; Ioannis Zabetakis. 2020. "Structural Elucidation of Irish Ale Bioactive Polar Lipids with Antithrombotic Properties." Biomolecules 10, no. 7: 1075.

Journal article
Published: 11 May 2020 in Microorganisms
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Glutathione S-Transferases (GSTs) comprise a diverse group of protein superfamily involved in cellular detoxification of various harmful xenobiotics and endobiotics. Cyanobacteria, being the primordial photosynthetic prokaryotes, served as an origin for the evolution of GSTs with diversity in their structures, substrate recognition, and catalytic functions. This study analysed the diversity of GSTs in cyanobacteria for the first time. Based on the sequence alignment and phylogenetic tree analysis, 12 GST classes were identified, which are distributed variedly within cyanobacterial orders such as four in Pleurocapsales, eight in Chroococcales, seven in Oscillatoriales, five in Stigonematales, and nine in Nostocales. Detailed evolutionary analysis of cyanobacterial GSTs suggested that the order Pleurocapsales served as the ancestry for GST evolution. The analysis also identified a conserved motif S[GLNTARS][ADE]I[LAI] with signature residues, cysteine, serine, and tyrosine at the N-terminal end that serves as the initiating residue for detoxification. Alternatively, the grouping of cyanobacterial GSTs and their unique signature residues were located, which serve as a possible discriminating factor. The study also described the mode of glutathione binding between the identified cyanobacterial GST groups highlighting the differences among the GST classes. New GST sequence data may improve further our understanding on GST evolution and other possible divergences in cyanobacteria.

ACS Style

Mohandass ShylajaNaciyar; Lakshmanan Karthick; Peter Arul Prakasam; Garlapati Deviram; Lakshmanan Uma; Dharmar Prabaharan; Sushanta Kumar Saha. Diversity of Glutathione S-Transferases (GSTs) in Cyanobacteria with Reference to Their Structures, Substrate Recognition and Catalytic Functions. Microorganisms 2020, 8, 712 .

AMA Style

Mohandass ShylajaNaciyar, Lakshmanan Karthick, Peter Arul Prakasam, Garlapati Deviram, Lakshmanan Uma, Dharmar Prabaharan, Sushanta Kumar Saha. Diversity of Glutathione S-Transferases (GSTs) in Cyanobacteria with Reference to Their Structures, Substrate Recognition and Catalytic Functions. Microorganisms. 2020; 8 (5):712.

Chicago/Turabian Style

Mohandass ShylajaNaciyar; Lakshmanan Karthick; Peter Arul Prakasam; Garlapati Deviram; Lakshmanan Uma; Dharmar Prabaharan; Sushanta Kumar Saha. 2020. "Diversity of Glutathione S-Transferases (GSTs) in Cyanobacteria with Reference to Their Structures, Substrate Recognition and Catalytic Functions." Microorganisms 8, no. 5: 712.

Journal article
Published: 29 October 2019 in Bioresource Technology Reports
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GABA (γ-aminobutyric acid) is a non-proteinogenic amino acid that plays a significant role in various health functions and has been identified in cyanobacteria. This investigation screened seventeen fast-growing Irish marine cyanobacteria as potential sustainable producers of GABA. Twelve of the seventeen cyanobacteria tested positive for GAD (glutamate decarboxylase) activity in vitro and were tested for their GABA content using a spectrophotometric assay. Five of the twelve cyanobacterial extracts (Calothrix contarenii SABC022701, Chlorogloea microcystoides SABC022904, Phormidium africanum SABC010301, P. angustissimum SABC022612 and P. laminosum SABC022613) showed the characteristic GABA peak with the amounts of GABA produced ranging from 0.99 × 104 to 72.84 × 104 nmol g−1 dry-weight biomass. These five cyanobacterial extracts were resolved by thin layer chromatography (TLC) to identify the GABA band, and the GABA bands from unstained TLC plate (same Rf values) were excised for verification of GABA spectrophotometrically. This is the first report on five potential Irish marine cyanobacteria as GABA producers.

ACS Style

Katie Shiels; Patrick Murray; Sushanta Kumar Saha. Marine cyanobacteria as potential alternative source for GABA production. Bioresource Technology Reports 2019, 8, 100342 .

AMA Style

Katie Shiels, Patrick Murray, Sushanta Kumar Saha. Marine cyanobacteria as potential alternative source for GABA production. Bioresource Technology Reports. 2019; 8 ():100342.

Chicago/Turabian Style

Katie Shiels; Patrick Murray; Sushanta Kumar Saha. 2019. "Marine cyanobacteria as potential alternative source for GABA production." Bioresource Technology Reports 8, no. : 100342.

Journal article
Published: 07 August 2019 in Biology
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Twenty-five marine cyanobacteria isolated from Irish coasts were characterized based on their morphological characters and 16S rRNA gene sequence analysis. In addition, superoxide dismutase (SOD) and malate dehydrogenase (MDH) isoenzyme banding patterns were used to differentiate two morphologically ambiguous isolates. In this study, six new cyanobacteria-specific primers were designed, and a 16S rRNA gene of twenty-five morphologically diverse cyanobacteria was successfully PCR amplified (1198–1396 bps). Assembled 16S rRNA sequences were used both for a basic local alignment search tool (BLAST) analysis for genus-level identification and to generate a phylogenetic tree, which yielded two major clusters: One with morphologically homogenous cyanobacteria and the other with morphologically very diverse cyanobacteria. Kamptonema okenii and Tychonema decoloratum were isolated from a single field sample of Ballybunion and were originally identified as the same ‘Oscillatoria sp.’ based on preliminary morphological observations. However, an alignment of 16S rRNA gene sequences and SOD and MDH isoenzyme banding pattern analyses helped in differentiating the morphologically-indistinguishable ‘Oscillatoria sp.’. Finally, after a re-evaluation of their morphological characters using modern taxonomic publications, the originally identified ‘Oscillatoria sp.’ were re-identified as Kamptonema okenii and Tychonema decoloratum, thus supporting the polyphasic approach of cyanobacteria characterization.

ACS Style

Katie Shiels; Norma Browne; Fiona Donovan; Patrick Murray; Sushanta Kumar Saha; Saha. Molecular Characterization of Twenty-Five Marine Cyanobacteria Isolated from Coastal Regions of Ireland. Biology 2019, 8, 59 .

AMA Style

Katie Shiels, Norma Browne, Fiona Donovan, Patrick Murray, Sushanta Kumar Saha, Saha. Molecular Characterization of Twenty-Five Marine Cyanobacteria Isolated from Coastal Regions of Ireland. Biology. 2019; 8 (3):59.

Chicago/Turabian Style

Katie Shiels; Norma Browne; Fiona Donovan; Patrick Murray; Sushanta Kumar Saha; Saha. 2019. "Molecular Characterization of Twenty-Five Marine Cyanobacteria Isolated from Coastal Regions of Ireland." Biology 8, no. 3: 59.

Journal article
Published: 18 January 2019 in Marine Drugs
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Marine and salmon polar lipids (PLs) extracted by conventional extractions with non-food-grade solvents (CE-salmon-PLs) possess antithrombotic bioactivities against platelet-activating factor (PAF) and thrombin. Similar effects of food-grade-extracted (FGE) marine PLs have not yet been reported. In this study, food-grade solvents were used to extract PLs from Irish organic farmed salmon (Salmo salar) fillets (FGE-salmon-PLs), while their antithrombotic bioactivities were assessed in human platelets induced by platelet aggregation agonists (PAF/thrombin). FGE-salmon-PLs were further separated by thin layer chromatography (TLC) into lipid subclasses, and the antithrombotic bioactivities of each subclass were also assessed. LC-MS was utilized to elucidate the structure-activity relationships. FGE-salmon-PLs strongly inhibited PAF-induced platelet aggregation, while their relevant anti-thrombin effects were at least three times more potent than the previously reported activities of CE-salmon-PLs. TLC-derived lipid fractions corresponding to phosphatidylcholines (PC) and phosphatidylethanolamines (PE) were the most bioactive lipid subclasses obtained, especially against thrombin. Their LC-MS analysis elucidated that they are diacyl- or alkyl-acyl- PC and PE moieties baring ω3 polyunsaturated fatty acids (PUFA) at their sn-2 position, such as eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA). Our results concerning the potent antithrombotic effects of FGE-salmon-PLs against both PAF and thrombin pathways strongly suggest that such food-grade extracts are putative candidates for the development of novel cardioprotective supplements and nutraceuticals.

ACS Style

Alexandros Tsoupras; Ronan Lordan; Katie Shiels; Sushanta Kumar Saha; Constantina Nasopoulou; Ioannis Zabetakis. In Vitro Antithrombotic Properties of Salmon (Salmo salar) Phospholipids in a Novel Food-Grade Extract. Marine Drugs 2019, 17, 62 .

AMA Style

Alexandros Tsoupras, Ronan Lordan, Katie Shiels, Sushanta Kumar Saha, Constantina Nasopoulou, Ioannis Zabetakis. In Vitro Antithrombotic Properties of Salmon (Salmo salar) Phospholipids in a Novel Food-Grade Extract. Marine Drugs. 2019; 17 (1):62.

Chicago/Turabian Style

Alexandros Tsoupras; Ronan Lordan; Katie Shiels; Sushanta Kumar Saha; Constantina Nasopoulou; Ioannis Zabetakis. 2019. "In Vitro Antithrombotic Properties of Salmon (Salmo salar) Phospholipids in a Novel Food-Grade Extract." Marine Drugs 17, no. 1: 62.

Review
Published: 14 June 2018 in Fermentation
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Cyanobacteria and microalgae have been cultivated only for a limited number of bioactive compounds or biotechnological applications such as for carotenoids; essential omega-3 fatty acids; phycobilipigments; live cells, unprocessed or minimally processed complete biomass as aqua feed, animal feed and human health supplements as rich sources of proteins, carbohydrates, pigments, vitamins and minerals. However, cyanobacteria and microalgae have been reported through several research investigations as a potential source for various bioactive molecules with marketable nutraceutical and pharmaceutical properties. Therefore, more cultivation of cyanobacteria and microalgae species are waiting for new biotechnological applications. At present, the global demand for microalgal applications is focused on biofuels including biodiesel and bioethanol apart from a handful (mentioned above) of bioactive compounds which are mostly used as nutraceuticals. Thus, microalgal biorefinery is growing rapidly for multiple commodities production from both conventional and photobioreactor-based cultivation for biomass feedstocks for various biotechnological applications. This review presents the cultivation aspects of selected cyanobacteria and microalgae for commercial purposes.

ACS Style

Sushanta Kumar Saha; Patrick Murray. Exploitation of Microalgae Species for Nutraceutical Purposes: Cultivation Aspects. Fermentation 2018, 4, 46 .

AMA Style

Sushanta Kumar Saha, Patrick Murray. Exploitation of Microalgae Species for Nutraceutical Purposes: Cultivation Aspects. Fermentation. 2018; 4 (2):46.

Chicago/Turabian Style

Sushanta Kumar Saha; Patrick Murray. 2018. "Exploitation of Microalgae Species for Nutraceutical Purposes: Cultivation Aspects." Fermentation 4, no. 2: 46.

Journal article
Published: 23 May 2018 in Marine Drugs
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While several marine polar lipids (PL) have exhibited cardioprotective properties through their effects on the platelet-activating factor (PAF) pathways, salmon PL have not been tested so far. In this study, the antithrombotic activities of salmon PL were assessed in human platelets and the structural characterisation of bioactive salmon PL was performed by GC-MS and LC-MS analyses. PL from fillets of Irish organic farmed salmon (Salmo salar) were extracted and separated into several lipid subclasses by thin-layer chromatography (TLC), while their fatty acid profile was fully characterised by GC-MS. Salmon total lipids (TL), total neutral lipids (TNL), total polar lipids (TPL), and each PL subclass obtained by TLC were further assessed for their in vitro effects towards PAF-induced and thrombin-induced platelet aggregation in human platelets. Salmon PL exhibited antithrombotic effects on human platelet aggregation, mostly through their strong inhibitory effects against the PAF pathway with IC50 values comparable to other marine PL, but with lower effects towards the thrombin pathway. PL fractions corresponding to phosphatidylcholine and phosphatidylethanolamine derivatives exhibited the most potent anti-PAF effects, while LC-MS analysis putatively elucidated their structure/function relationship. Several diacyl-PC/PE and alkyl-acyl-PC/PE species containing mostly docosahexaenoic acid at their sn-2 glycerol-backbone may be responsible for the bioactivity. The data presented suggests that salmon contains PL with strong antithrombotic bioactivities.

ACS Style

Alexandros Tsoupras; Ronan Lordan; Martina Demuru; Katie Shiels; Sushanta Kumar Saha; Constantina Nasopoulou; Ioannis Zabetakis. Structural Elucidation of Irish Organic Farmed Salmon (Salmo salar) Polar Lipids with Antithrombotic Activities. Marine Drugs 2018, 16, 176 .

AMA Style

Alexandros Tsoupras, Ronan Lordan, Martina Demuru, Katie Shiels, Sushanta Kumar Saha, Constantina Nasopoulou, Ioannis Zabetakis. Structural Elucidation of Irish Organic Farmed Salmon (Salmo salar) Polar Lipids with Antithrombotic Activities. Marine Drugs. 2018; 16 (6):176.

Chicago/Turabian Style

Alexandros Tsoupras; Ronan Lordan; Martina Demuru; Katie Shiels; Sushanta Kumar Saha; Constantina Nasopoulou; Ioannis Zabetakis. 2018. "Structural Elucidation of Irish Organic Farmed Salmon (Salmo salar) Polar Lipids with Antithrombotic Activities." Marine Drugs 16, no. 6: 176.

Research article
Published: 30 April 2018 in BioMed Research International
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Dunaliella salina is the popular microalga for β-carotene production. There is still a growing demand for the best strain identification and growth conditions optimization for maximum carotenoids production. Some strains are noncarotenogenic while other strains may respond differently to applied growth conditions and produce enhanced carotenoid levels. This study tested the carotenogenic ability of Dunaliella salina CCAP 19/20 under sixteen stress conditions and certain biochemical changes in response to specific stress were investigated. This study identified the above strain as carotenogenic, which produces maximum carotenoids under high light (240 μmol photons m−2 sec−1) when combined nitrogen and micronutrients (Cu or CuMn) were limited. Based on the intensity of extracted ions chromatograms, lutein (m/z 568.4357) appears as the major carotenoid followed by β-carotene (m/z 536.4446) and α-carotene (m/z 536.4435). A polypeptide of 28.3 kDa appeared while another polypeptide of 25.5 kDa disappeared in stress cells as compared to noncarotenogenic cells. Expression levels of antioxidative-enzyme superoxide dismutase-1 (SOD1, H2O2-resistant) remained identical, while the prominent H2O2-sensitive isoforms SOD2 and SOD3 were downregulated during carotenogenic conditions. Overall, increased carotenoids levels might be due to the response of differential expression of specific polypeptides and retention of H2O2-resistant SOD, which eventually might help the organism to thrive in the tested stress conditions.

ACS Style

Sushanta Kumar Saha; Naresh Kazipet; Patrick Murray. The Carotenogenic Dunaliella salina CCAP 19/20 Produces Enhanced Levels of Carotenoid under Specific Nutrients Limitation. BioMed Research International 2018, 2018, 1 -11.

AMA Style

Sushanta Kumar Saha, Naresh Kazipet, Patrick Murray. The Carotenogenic Dunaliella salina CCAP 19/20 Produces Enhanced Levels of Carotenoid under Specific Nutrients Limitation. BioMed Research International. 2018; 2018 ():1-11.

Chicago/Turabian Style

Sushanta Kumar Saha; Naresh Kazipet; Patrick Murray. 2018. "The Carotenogenic Dunaliella salina CCAP 19/20 Produces Enhanced Levels of Carotenoid under Specific Nutrients Limitation." BioMed Research International 2018, no. : 1-11.

Journal article
Published: 01 January 2018 in Open Access Journal of Microbiology & Biotechnology
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ACS Style

Sushanta Kumar Saha. Microalgae and Cyanobacteria: The Heroes of Growing Industrial Biotechnology Sectors. Open Access Journal of Microbiology & Biotechnology 2018, 3, 1 .

AMA Style

Sushanta Kumar Saha. Microalgae and Cyanobacteria: The Heroes of Growing Industrial Biotechnology Sectors. Open Access Journal of Microbiology & Biotechnology. 2018; 3 (1):1.

Chicago/Turabian Style

Sushanta Kumar Saha. 2018. "Microalgae and Cyanobacteria: The Heroes of Growing Industrial Biotechnology Sectors." Open Access Journal of Microbiology & Biotechnology 3, no. 1: 1.

Book chapter
Published: 27 March 2015 in Phycotoxins
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ACS Style

Sushanta Kumar Saha; Edward McHugh; Patrick Murray; Daniel J. Walsh. Microalgae as a source of nutraceuticals. Phycotoxins 2015, 255 -291.

AMA Style

Sushanta Kumar Saha, Edward McHugh, Patrick Murray, Daniel J. Walsh. Microalgae as a source of nutraceuticals. Phycotoxins. 2015; ():255-291.

Chicago/Turabian Style

Sushanta Kumar Saha; Edward McHugh; Patrick Murray; Daniel J. Walsh. 2015. "Microalgae as a source of nutraceuticals." Phycotoxins , no. : 255-291.

Journal article
Published: 01 November 2013 in Bioresource Technology
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The aim of this study was to assess the effects of sixteen stress conditions on total carotenoid production and the response of antioxidative enzyme superoxide dismutase (SOD) in microalga Dunaliella salina. Of the stress conditions tested, high-light illumination (240 μmol photons m(-2) s(-1)) in combination with nitrogen depletion were the conditions associated with maximum carotenoid production and which induced Fe-SOD and retained the specific Mn-SOD isoform. Removal of the micronutrients manganese (Mn), Zinc (Zn) and Iron (Fe) as well as nitrogen from the medium enhanced carotenoid production on day 5, while the removal of nitrogen and Mn from the growth medium drastically affected carotenoid production at all time-points. The differential response of SODs influences the levels of carotenoid biosynthesis as chronic molecular defence strategies of D. salina.

ACS Style

Sushanta Kumar Saha; Siobhan Moane; Patrick Murray. Effect of macro- and micro-nutrient limitation on superoxide dismutase activities and carotenoid levels in microalga Dunaliella salina CCAP 19/18. Bioresource Technology 2013, 147, 23 -28.

AMA Style

Sushanta Kumar Saha, Siobhan Moane, Patrick Murray. Effect of macro- and micro-nutrient limitation on superoxide dismutase activities and carotenoid levels in microalga Dunaliella salina CCAP 19/18. Bioresource Technology. 2013; 147 ():23-28.

Chicago/Turabian Style

Sushanta Kumar Saha; Siobhan Moane; Patrick Murray. 2013. "Effect of macro- and micro-nutrient limitation on superoxide dismutase activities and carotenoid levels in microalga Dunaliella salina CCAP 19/18." Bioresource Technology 147, no. : 23-28.

Journal article
Published: 12 March 2013 in Biotechnology Letters
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To understand the effect of any biomolecules in specific metabolic pathways in humans, bioavailability and for other basic understanding, stable isotopically-labelled biomolecules (preferably deuterated) is the fundamental pre-requisite. Production of deuterated biomolecules such as, astaxanthin, β-carotene, lutein, chlorophyll-a, and eicosapentaenoic acid (EPA, 20:5n-3) by metabolic tagging have been shown in commercially important microalgae, Haematococcus pluvialis and Phaeodactylum tricornutum. These microalgae were grown in appropriate optimized medium supplemented with 25% (v/v) deuterated water. LC-MS analysis showed a maximum of 20, 25, 23, 24, and 27% replacement of hydrogen by deuterium atoms respectively in astaxanthin, β-carotene, lutein, chlorophyll-a, and EPA. To our knowledge, this is the first report on the production of deuterated astaxanthin, chlorophyll-a and EPA by these microalgae.

ACS Style

Sushanta Kumar Saha; Jeremiah Hayes; Siobhan Moane; Patrick Murray. Tagging of biomolecules with deuterated water (D2O) in commercially important microalgae. Biotechnology Letters 2013, 35, 1067 -1072.

AMA Style

Sushanta Kumar Saha, Jeremiah Hayes, Siobhan Moane, Patrick Murray. Tagging of biomolecules with deuterated water (D2O) in commercially important microalgae. Biotechnology Letters. 2013; 35 (7):1067-1072.

Chicago/Turabian Style

Sushanta Kumar Saha; Jeremiah Hayes; Siobhan Moane; Patrick Murray. 2013. "Tagging of biomolecules with deuterated water (D2O) in commercially important microalgae." Biotechnology Letters 35, no. 7: 1067-1072.

Journal article
Published: 01 January 2013 in Bioresource Technology
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To maximize the biomass and lipid production for applications in food or biofuel feedstock, nine stress conditions were tested considering N and/or P limitations, light intensity & quality, for Haematococcus pluvialis SCCAP K-0084 cultivation. Photosynthetically active radiation (PAR), warm white light emitting diode (WWLED), and white light emitting diode (WLED) at illumination of 240 μmol photons m(-2) sec(-1) were the best stress-regulatory factors. PAR without P & low N conditions yielded high biomass with 33% lipids containing increased C16:0 and C18:0 saturated fatty acids, and reduced unsaturated fatty acids (UFAs) (oleic, linoleic, and α/γ-linolenic). WWLED and WLED without P conditions also yielded high biomass, but 25% lipids with increased amounts of UFAs. Red light emitting diode (RLED) without P & low N conditions yielded 46% lipids with lowest biomass. PAR and WWLED & WLED illuminated conditions were found suitable respectively for biodiesel feedstock lipids and UFA-rich lipids for multiple applications.

ACS Style

Sushanta Kumar Saha; Edward McHugh; Jeremiah Hayes; Siobhan Moane; Daniel Walsh; Patrick Murray. Effect of various stress-regulatory factors on biomass and lipid production in microalga Haematococcus pluvialis. Bioresource Technology 2013, 128, 118 -124.

AMA Style

Sushanta Kumar Saha, Edward McHugh, Jeremiah Hayes, Siobhan Moane, Daniel Walsh, Patrick Murray. Effect of various stress-regulatory factors on biomass and lipid production in microalga Haematococcus pluvialis. Bioresource Technology. 2013; 128 ():118-124.

Chicago/Turabian Style

Sushanta Kumar Saha; Edward McHugh; Jeremiah Hayes; Siobhan Moane; Daniel Walsh; Patrick Murray. 2013. "Effect of various stress-regulatory factors on biomass and lipid production in microalga Haematococcus pluvialis." Bioresource Technology 128, no. : 118-124.

Journal article
Published: 15 May 2011 in Journal of Bacteriology
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The upstream intergenic regions for each of four genes encoding Ser/Thr kinases, all2334, pknE (alr3732), all4668, and all4838, were fused to a gfpmut2 reporter gene to determine their expression during heterocyst development in the cyanobacterium Anabaena ( Nostoc ) sp. strain PCC 7120. P pknE -gfp was upregulated after nitrogen step-down and showed strong expression in differentiating cells. Developmental regulation of pknE required a 118-bp upstream region and was abolished in a hetR mutant. A pknE mutant strain had shorter filaments with slightly higher heterocyst frequency than did the wild type. Overexpression of pknE from its native promoter inhibited heterocyst development in the wild type and in four mutant backgrounds that overproduce heterocysts. Overexpression of pknE from the copper-inducible petE promoter did not completely inhibit heterocyst development but caused a 24-h delay in heterocyst differentiation and cell bleaching 4 to 5 days after nitrogen step-down. Strains overexpressing pknE and containing P hetR -gfp or P patS -gfp reporters failed to show developmental regulation of the reporters and had undetectable levels of HetR protein. Genetic epistasis experiments suggest that overexpression of pknE blocks HetR activity or downstream regulation.

ACS Style

Sushanta K. Saha; James W. Golden. Overexpression of pknE Blocks Heterocyst Development in Anabaena sp. Strain PCC 7120. Journal of Bacteriology 2011, 193, 2619 -2629.

AMA Style

Sushanta K. Saha, James W. Golden. Overexpression of pknE Blocks Heterocyst Development in Anabaena sp. Strain PCC 7120. Journal of Bacteriology. 2011; 193 (10):2619-2629.

Chicago/Turabian Style

Sushanta K. Saha; James W. Golden. 2011. "Overexpression of pknE Blocks Heterocyst Development in Anabaena sp. Strain PCC 7120." Journal of Bacteriology 193, no. 10: 2619-2629.

Journal article
Published: 11 February 2011 in Journal of Bacteriology
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The filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 produces specialized cells for nitrogen fixation called heterocysts. Previous work showed that the group 2 sigma factor sigE (alr4249; previously called sigF) is upregulated in differentiating heterocysts 16 h after nitrogen step-down. We now show that the sigE gene is required for normal heterocyst development and normal expression levels of several heterocyst-specific genes. Mobility shift assays showed that the transcription factor NtcA binds to sites in the upstream region of sigE and that this binding is enhanced by 2-oxoglutarate (2-OG). Deletions of the region containing the NtcA binding sites in P(sigE)-gfp reporter plasmids showed that the sites contribute to normal developmental regulation but are not essential for upregulation in heterocysts. Northern RNA blot analysis of nifH mRNA revealed delayed and reduced transcript levels during heterocyst differentiation in a sigE mutant background. Quantitative reverse transcription-PCR (qRT-PCR) analyses of the sigE mutant showed lower levels of transcripts for nifH, fdxH, and hglE2 but normal levels for hupL. We developed a P(nifHD)-gfp reporter construct that showed strong heterocyst-specific expression. Time-lapse microscopy of the P(nifHD)-gfp reporter in a sigE mutant background showed delayed development and undetectable green fluorescent protein (GFP) fluorescence. Overexpression of sigE caused accelerated heterocyst development, an increased heterocyst frequency, and premature expression of GFP fluorescence from the P(nifHD)-gfp reporter.

ACS Style

Rodrigo A. Mella-Herrera; M. Ramona Neunuebel; Krithika Kumar; Sushanta Kumar Saha; James W. Golden. The sigE Gene Is Required for Normal Expression of Heterocyst-Specific Genes in Anabaena sp. Strain PCC 7120. Journal of Bacteriology 2011, 193, 1823 -1832.

AMA Style

Rodrigo A. Mella-Herrera, M. Ramona Neunuebel, Krithika Kumar, Sushanta Kumar Saha, James W. Golden. The sigE Gene Is Required for Normal Expression of Heterocyst-Specific Genes in Anabaena sp. Strain PCC 7120. Journal of Bacteriology. 2011; 193 (8):1823-1832.

Chicago/Turabian Style

Rodrigo A. Mella-Herrera; M. Ramona Neunuebel; Krithika Kumar; Sushanta Kumar Saha; James W. Golden. 2011. "The sigE Gene Is Required for Normal Expression of Heterocyst-Specific Genes in Anabaena sp. Strain PCC 7120." Journal of Bacteriology 193, no. 8: 1823-1832.

Journal article
Published: 31 May 2010 in Bioresource Technology
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Removal of combined nitrogen and addition of Poly R-478 to the growth medium enhanced oxidative stress, and altered the activities of ligninolytic enzymes of Oscillatoria willei BDU 130511. The activities of ligninolytic and antioxidative enzymes (LiP-like, LAC, PPO, SOD, POD, CAT, and APX) were increased upon nitrogen limitation and dye supplementation. The metabolic enzymes tested (GR, GPX, EST, and MDH) showed differential expressions under varied growth conditions. Up on nitrogen limitation, O. willei BDU 130511 showed enhanced ligninolytic activity as shown by α-keto-γ-methylthiolbutyric acid (KTBA) oxidation and increased H2O2 production. The organism decolourized 52% of Poly R-478 due to partial degradation and adsorption of dye particles from dye-added medium after 7 days of growth. This manuscript discusses the responses of ligninolytic and antioxidative enzymes of O. willei BDU 130511 during Poly R-478 decolourization/degradation, and the organism’s potential in bioremediation.

ACS Style

Sushanta Kumar Saha; Palanisami Swaminathan; C. Raghavan; Lakshmanan Uma; Gopalakrishnan Subramanian. Ligninolytic and antioxidative enzymes of a marine cyanobacterium Oscillatoria willei BDU 130511 during Poly R-478 decolourization. Bioresource Technology 2010, 101, 3076 -3084.

AMA Style

Sushanta Kumar Saha, Palanisami Swaminathan, C. Raghavan, Lakshmanan Uma, Gopalakrishnan Subramanian. Ligninolytic and antioxidative enzymes of a marine cyanobacterium Oscillatoria willei BDU 130511 during Poly R-478 decolourization. Bioresource Technology. 2010; 101 (9):3076-3084.

Chicago/Turabian Style

Sushanta Kumar Saha; Palanisami Swaminathan; C. Raghavan; Lakshmanan Uma; Gopalakrishnan Subramanian. 2010. "Ligninolytic and antioxidative enzymes of a marine cyanobacterium Oscillatoria willei BDU 130511 during Poly R-478 decolourization." Bioresource Technology 101, no. 9: 3076-3084.