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Effects of elevated ultraviolet radiation on primary metabolites in selected alpine algae and cyanobacteria.

Hartmann A, Albert A, Ganzera M - J. Photochem. Photobiol. B, Biol. (2015)

Bottom Line: Besides changes in pigment composition we discovered that primary polar metabolites like aromatic amino acids, nucleic bases and nucleosides are increasingly produced when the organisms are exposed to elevated UV radiation.Respective compounds were isolated and identified, and in order to quantify them an HPLC-DAD method was developed and validated.Our results show that especially tyrosine and guanosine were found to be generally two to three times upregulated in the UV-B exposed samples compared to the non-treated control.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pharmacy, Pharmacognosy, University of Innsbruck, 6020 Innsbruck, Austria.

No MeSH data available.


Sun simulator spectra for control (gray line) and treatment (black line) during the experiments; (A) spectra covering the range 300–800 nm; and (B) detail representing the relevant range from 280 to 400 nm.
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Figure 1: Sun simulator spectra for control (gray line) and treatment (black line) during the experiments; (A) spectra covering the range 300–800 nm; and (B) detail representing the relevant range from 280 to 400 nm.

Mentions: The irradiation of the algae was carried out in the sun simulator of the Helmholtz Center in Munich, Germany. The simulated photobiological conditions provided exposure very close to global solar radiation from UV to near infrared radiation using a combination of four different types of lamps (metal halide lamps, quartz halogen lamps, blue fluorescence tubes, and UV-B fluorescence tubes). The arrangement of many of these lamps in several groups allowed us to simulate also the diurnal variation of solar radiation by switching on and off appropriate groups. Soda-lime and acrylic glass filters were used to prevent the biological material from damage by UV-C radiation (100–280 nm), emitted by UV-B fluorescence tubes, and to adjust the short-wave cut-off in the UV-B spectrum [21-23]. The UV exposure of the algae was performed in a sun simulator, which was divided into two compartments. The right part was covered by soda-lime and acrylic glass filters to allow exposure to UV-A, UV-B radiation and PAR, whereas the left part was covered by normal float glass to eliminate UV-B radiation. The experiments were carried out for 3 days using the first 24 h as an adaptation phase for the organisms. In this period no UV-B radiation was supplied (control). Irradiation experiments were then subsequently carried out on day two and three, always providing 14 h of UV-B irradiation per day. Additionally, a light–dark cycle of 16:8 h was set, i.e. PAR was switched on one hour before the onset of UV-B radiation and switched off one hour after UV-B exposure. During the UV-B treatment the algae were exposed to elevated UV-B radiation of 2.8 W/m2 and UV-A radiation of 13.4 W/m2, whereas the control only obtained UV-A radiation of 7.0 W/m2. Maximum PAR was set to 340 μmol/m2/s during UV-B exposure (Fig. 1). Temperature was controlled at 20 °C and a constant relative air humidity of 90% was adjusted to avoid desiccation stress. The algae were exposed to these conditions in open glass petri dishes (180 × 30 mm; Steriplan, VWR, Vienna, Austria). Prior to the experiments the algae culture broth was equally divided into 15 petri dishes for each species, during the experiments Bolds Basal culture medium was regularly added to keep the liquid level in each petri dish constantly at 1 cm. After 24 h (adaption phase) 3 petri dishes were removed and used as a non-irradiated control. Subsequently, after 48 h and 72 h again 3 petri dishes were removed from each compartment; the study design is shown in Fig. S1 (supplementary material).


Effects of elevated ultraviolet radiation on primary metabolites in selected alpine algae and cyanobacteria.

Hartmann A, Albert A, Ganzera M - J. Photochem. Photobiol. B, Biol. (2015)

Sun simulator spectra for control (gray line) and treatment (black line) during the experiments; (A) spectra covering the range 300–800 nm; and (B) detail representing the relevant range from 280 to 400 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4509709&req=5

Figure 1: Sun simulator spectra for control (gray line) and treatment (black line) during the experiments; (A) spectra covering the range 300–800 nm; and (B) detail representing the relevant range from 280 to 400 nm.
Mentions: The irradiation of the algae was carried out in the sun simulator of the Helmholtz Center in Munich, Germany. The simulated photobiological conditions provided exposure very close to global solar radiation from UV to near infrared radiation using a combination of four different types of lamps (metal halide lamps, quartz halogen lamps, blue fluorescence tubes, and UV-B fluorescence tubes). The arrangement of many of these lamps in several groups allowed us to simulate also the diurnal variation of solar radiation by switching on and off appropriate groups. Soda-lime and acrylic glass filters were used to prevent the biological material from damage by UV-C radiation (100–280 nm), emitted by UV-B fluorescence tubes, and to adjust the short-wave cut-off in the UV-B spectrum [21-23]. The UV exposure of the algae was performed in a sun simulator, which was divided into two compartments. The right part was covered by soda-lime and acrylic glass filters to allow exposure to UV-A, UV-B radiation and PAR, whereas the left part was covered by normal float glass to eliminate UV-B radiation. The experiments were carried out for 3 days using the first 24 h as an adaptation phase for the organisms. In this period no UV-B radiation was supplied (control). Irradiation experiments were then subsequently carried out on day two and three, always providing 14 h of UV-B irradiation per day. Additionally, a light–dark cycle of 16:8 h was set, i.e. PAR was switched on one hour before the onset of UV-B radiation and switched off one hour after UV-B exposure. During the UV-B treatment the algae were exposed to elevated UV-B radiation of 2.8 W/m2 and UV-A radiation of 13.4 W/m2, whereas the control only obtained UV-A radiation of 7.0 W/m2. Maximum PAR was set to 340 μmol/m2/s during UV-B exposure (Fig. 1). Temperature was controlled at 20 °C and a constant relative air humidity of 90% was adjusted to avoid desiccation stress. The algae were exposed to these conditions in open glass petri dishes (180 × 30 mm; Steriplan, VWR, Vienna, Austria). Prior to the experiments the algae culture broth was equally divided into 15 petri dishes for each species, during the experiments Bolds Basal culture medium was regularly added to keep the liquid level in each petri dish constantly at 1 cm. After 24 h (adaption phase) 3 petri dishes were removed and used as a non-irradiated control. Subsequently, after 48 h and 72 h again 3 petri dishes were removed from each compartment; the study design is shown in Fig. S1 (supplementary material).

Bottom Line: Besides changes in pigment composition we discovered that primary polar metabolites like aromatic amino acids, nucleic bases and nucleosides are increasingly produced when the organisms are exposed to elevated UV radiation.Respective compounds were isolated and identified, and in order to quantify them an HPLC-DAD method was developed and validated.Our results show that especially tyrosine and guanosine were found to be generally two to three times upregulated in the UV-B exposed samples compared to the non-treated control.

View Article: PubMed Central - PubMed

Affiliation: Institute of Pharmacy, Pharmacognosy, University of Innsbruck, 6020 Innsbruck, Austria.

No MeSH data available.