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Transglutaminase activity decrease during acclimation to hyposaline conditions in marine seaweed Grateloupia
Pilar García-Jiménez1, Pilar M Just, Ancor M Delgado
1Departamento de Biología, Facultad de Ciencias del Mar, Universidad de Las Palmas de Gran Canaria, ES-35017 Las Palmas de Gran Canaria, Spain.
Journal of Plant Physiology
|August 8, 2006
Summary
Polyamines like putrescine, spermidine, and spermine increased in red algae under hyposalinity. This response, linked to altered enzyme activity, suggests polyamines are crucial for marine algae adapting to changing salt conditions.
Area of Science:
- Marine Biology
- Plant Physiology
- Biochemistry
Background:
- Polyamines (PAs) are vital compounds involved in cellular processes.
- Environmental stressors, particularly salt stress, impact marine organisms.
- Red algae possess unique physiological mechanisms for stress adaptation.
Purpose of the Study:
- To investigate the role of polyamines (PAs) in the acclimation of the marine red alga Grateloupia doryphora to hyposaline conditions.
- To understand the biochemical changes associated with PA metabolism under reduced salinity.
Main Methods:
- Grateloupia doryphora was incubated in hyposaline (18 psu) and natural (36 psu) seawater.
- Levels of free polyamines (putrescine, spermidine, spermine) were measured.
- Key enzyme activities involved in PA synthesis and metabolism (TGase, ODC, arginase, ADC) were assessed.
- Photosynthetic rates were determined under different salinity conditions.
Main Results:
- A moderate hyposaline shock (18 psu) significantly increased free putrescine (PUT), spermidine (SPD), and spermine (SPM) levels.
- Increased PA levels were associated with decreased TGase activity and altered arginine-dependent PA synthesis pathways (ODC and arginase decreased, ADC increased).
- Photosynthetic rates increased in algae exposed to free SPD at 18 psu, but not at 36 psu.
Conclusions:
- Polyamines play a significant role in the acclimation of Grateloupia doryphora to moderate hyposaline stress.
- Changes in PA levels and associated enzyme activities are key components of the stress response.
- Spermidine may directly enhance photosynthetic efficiency under hyposaline conditions.
