Effects of Salinity Changes on the Growth of Dunaliella salina and Its Isozyme Activities of Glycerol-3-phosphate Dehydrogenase

Abstract

Dunaliella salina could survive in media containing a wide range of NaCl concentrations ranging from about 0.05 M to saturation (around 5.5 M). Glycerol is an important osmolyte when Dunaliella survive in various salt environments, and G3pdh is a key enzyme in glycerol metabolism. The osmotic response of D. salina was investigated by studying its cell growth, glycerol content change, and isozyme activity of glycerol-3-phosphate dehydrogenase (G3pdh) in different salinities. Results showed that 2.0 M NaCl was the optimal salinity for the growth of D. salina, in which condition the highest glycerol content of 64.02 +/- 3.21 (mean +/- SD) microg/mL was detected. D. salina could rapidly increase or decrease glycerol contents to adapt to hypoosmotic or hyperosmotic environments. The glycerol content declined 52.05% when salinity was changed from 2.0 to 0.5 M NaCl, and the glycerol content increased 43.61% when salinity was increased from 2.0 to 5.0 M NaCl. In the isozyme electrophoresis assay two kinds of isozymes, G3pdh and superoxide dismutase (Sod), were detected synchronously. Interestingly, it was first found that there are five isozymes of G3pdh in D. salina. G3pdh-2 mainly takes effect in moderate to high salinities, whereas the other four isozymes take effect in low salinities, which may provide an important clue for future research on osmoregulation mechanisms.

Salinity-Induced Effects in the Halophyte Suaeda salsa Using NMR-based Metabolomics

“…High soil salinity can inhibit the growth of plants including both non-halophyte and halophyte (Song et al 2008;Chen et al 2009). In our case, the high salinity (500 mM NaCl) significantly (p<0.01) inhibited the growth of S. salsa after 1 month exposure (Table 1).…”

Effects of Depth and Concentration of Digestate on Growth of Three Microalgal Species

“…is a group of halotolerant, motile microalgae that survive a wide range of stress factors. D. tertiolecta, for example, can survive in a wide range of NaCl concentrations, from 0.05 M to 5.5 M, and of pH values, from 1 to 11, even under intense light and high temperature conditions [7,8].…”

Propyl gallate promotes salt stress tolerance in green microalga Dunaliella salina by reducing free radical oxidants and enhancing β-carotene production

“…To remove ROS, plants have a ROS-scavenging system comprising non-enzymatic antioxidants, such as ascorbate, salicylate, carotenoids, tochopherols, and enzymatic antioxidants such as catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD) (Foyer and Noctor 2003;Sairam and Tyagi 2004). Although salt resistant plants and algae are adapted to salinity by ion homeostasis, osmolyte biosynthesis and ion compartmentalization, the presence of an antioxidant system is essential for the impressive elimination of ROS (Mittler 2002;Liska et al 2004;Chen et al 2009). Based on several studies, it is clear that salt adaptation is often associated well with the activity of an antioxidant system (Noctor and Foyer 1998;Bor et al 2003;Azevedo Neto et al 2006;Gapinska et al 2008;Munns and Tester 2008).…”

“…Dunaliella is a unicellular and economically important green alga, which can survive in a wide range of salt concentrations, between 0.5 and 5 M (Ben-Amotz and Avron 1983b; Chen et al 2009). Because of high flexibility and tolerance under different unfavorable conditions, it is frequently considered as an interesting experimental model for studying stress physiology (Cowan et al 1992).…”