News Column

Research Data from Sabanci University Update Understanding of Nitrogen

June 17, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- Investigators discuss new findings in Nitrogen. According to news reporting originating in Istanbul, Turkey, by NewsRx journalists, research stated, "Green algae offer sustainable, clean and eco-friendly energy resource. However, production efficiency needs to be improved."

The news reporters obtained a quote from the research from Sabanci University, "Increasing cellular lipid levels by nitrogen depletion is one of the most studied strategies. Despite this, the underlying physiological and biochemical mechanisms of this response have not been well defined. Algae species adapted to hypersaline conditions can be cultivated in salty waters which are not useful for agriculture or consumption. Due to their inherent extreme cultivation conditions, use of hypersaline algae species is better suited for avoiding culture contamination issues. In this study, we identified a new halophilic Dunaliella salina strain by using 18S ribosomal RNA gene sequencing. We found that growth and biomass productivities of this strain were directly related to nitrogen levels, as the highest biomass concentration under 0.05 mM or 5 mM nitrogen regimes were 495 mg/l and 1409 mg/l, respectively. We also confirmed that nitrogen limitation increased cellular lipid content up to 35% under 0.05 mM nitrogen concentration. In order to gain insight into the mechanisms of this phenomenon, we applied fluorometric, flow cytometric and spectrophotometric methods to measure oxidative stress and enzymatic defence mechanisms. Under nitrogen depleted cultivation conditions, we observed increased lipid peroxidation by measuring an important oxidative stress marker, malondialdehyde and enhanced activation of catalase, ascorbate peroxidase and superoxide dismutase antioxidant enzymes. These observations indicated that oxidative stress is accompanied by increased lipid content in the green alga. In addition, we also showed that at optimum cultivation conditions, inducing oxidative stress by application of exogenous H2O2 leads to increased cellular lipid content up to 44% when compared with non-treated control groups. Our results support that oxidative stress and lipid overproduction are linked. Importantly, these results also suggest that oxidative stress mediates lipid accumulation."

According to the news reporters, the research concluded: "Understanding such relationships may provide guidance for efficient production of algal biodiesels."

For more information on this research see: Oxidative stress is a mediator for increased lipid accumulation in a newly isolated Dunaliella salina strain. Plos One, 2014;9(3):e91957. (Public Library of Science - www.plos.org; Plos One - www.plosone.org)

Our news correspondents report that additional information may be obtained by contacting K. Yilancioglu, Faculty of Engineering and Natural Sciences, Sabanci University, Orhanl?, Istanbul, Turkey. Additional authors for this research include M. Cokol, I. Pastirmaci, B. Erman and S. Cetiner (see also Nitrogen).

Keywords for this news article include: Turkey, Eurasia, Istanbul, Nitrogen.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Life Science Weekly


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