SEARCH

SEARCH BY CITATION

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

We investigated the effects of salinity and artificial UV radiation on the accumulation of mycosporine-like amino acids (MAAs) in sexual and parthenogenetic Artemia from Lake Urmia. The nauplii hatched from the cysts were cultured until adulthood under two salinities (150 and 250 g L−1) and two light treatments (PAR and PAR+UVR) in the laboratory. Finally, the Artemia were analyzed for their concentration of MAAs. In most of the cases, the higher salinity level applied was found to increase the MAA concentrations in both Artemia populations significantly. The acquisition efficiency of MAAs in both Artemia populations increased under exposure to UVR-supplemented photosynthetically active radiation (PAR) compared to those raised under PAR, except for Porphyra-334. It was observed that combination of UV radiation and elevated salinity significantly increased the bioaccumulation of MAAs. Thus, the presence of these compounds in these populations of Artemia may increase their adaptability for living in high-UV and high-salinity conditions prevailing in Lake Urmia. Higher concentrations of MAAs in the parthenogenetic population of Artemia could be probably attributed to its mono sex nature and higher adaptation capacities to extreme environmental conditions.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

The visible range of the solar electromagnetic spectrum (photosynthetically active radiation = PAR, 400–700 nm) provides the energy required for the photosynthetic process and thus has a key ecosystemic role. The shorter wavelengths of the spectrum referred to as ultraviolet radiation (UVR, 280–400 nm), especially ultraviolet-B (UV-B, 280–320 nm), have been reported to cause a number of deleterious effects such as genetic, physiologic and ecological damages in various organisms [1-6]. Terrestrial, marine and freshwater organisms have developed strategies to diminish the direct and indirect damaging effects of environmental UVR by synthesizing, accumulating and metabolizing a variety of UV-absorbing substances called mycosporine-like amino acids (MAAs) [7-10]. MAAs, cyclohexenone and cyclohexenimine chromophores, conjugated with the nitrogen substituent of an amino acid or its imino alcohol, are small water-soluble compounds with absorption maxima ranging from 310 to 360 nm [7, 9]. Considerable interest has been centered on MAAs because experimental evidence indicates that in marine organisms the major functions of MAAs are to act as active UV filters [10-13] and/or as antioxidants [7, 10, 14, 15].

Several other hypotheses about the role of MAAs in biological systems have been formulated: (1) they may contribute to osmotic regulation [16-18], (2) they may act as regulatory metabolites of sporulation and germination in fungi [19], and in the reproduction in marine invertebrates [20-22], (3) they may play a role under desiccation or thermal stress in certain organisms [18, 23] and finally (4) they can act as an intracellular nitrogen reservoir [24]. Recently, Kicklighter et al. [25] showed that pyrimidines and MAAs function as alarm cues in the defensive secretions of the sea hare Aplysia californica.

As documented above, several studies have suggested the antistress effects of MAAs in different organisms. Hence, we used the brine shrimp Artemia as a model organism, occurring in the surface zooplankton of saline waters. The genus Artemia (brine shrimp) with various geographical species and strains is commonly considered to be a worldwide euryhaline organism that is well known for its ability to adapt to diverse biotopes (inland salt lakes, coastal lagoons and solar salt pools) with variable salinity ranging from 10 g L−1 [26, 27] to 340 g L−1 [28, 29]. It comprises bisexual species, which are found on all continents except Antarctica, and parthenogenetic populations, which are endemic to Europe, Asia and Australia [27]. In Iran, the genus Artemia is known to occur in at least 17 salt lakes, salty rivers and lagoons from 11 provinces [26]. Artemia urmiana is the only bisexual population found in Lake Urmia, while the rest of Iranian Artemia are parthenogenetic [26, 27].

Lake Urmia is a thalassohaline, sodium chloride lake with oligotrophic characteristics, located in Northwestern (37°20′N, 45°40′E) Iran [30]. The water salinity range of Lake Urmia used to be between 140 and 220 g L−1 before 1999 but its salinity has reached levels as high as 300 g L−1 due to drought since 2000 [27]. Lake Urmia is the natural habitat of A. urmiana, first reported by Günther [31]. The presence of a parthenogenetic Artemia population in the temporary small costal lagoons of Lake Urmia was initially reported by Agh and Noori [32] and later by Agh et al. [27]. These lagoons are scattered all around the lake, present small to large areas (up to 10 000 m2) and their depths are below 0.7 m [33]. Water salinity in these lagoons ranges from 10 to 20 g L−1 in early spring to saturated level in early summer.

Since the beginning of a drought period in 1997, the salinity of Lake Urmia has increased year by year attaining complete saturation, putting the life of its fauna and flora including, A. urmiana and parthenogenetic Artemia, at high risk [27]. Therefore, a considerable interest has been centered on Artemia strategies to deal with current hypersaline and elevated UV radiation conditions. Thus, the objective of this work was to study bioaccumulation of MAAs in A. urmiana and a parthenogenetic Artemia under different salinity and UV radiation levels. We also tried to find out the relationship between photoprotective and potential osmoregulatory functions of MAAs in these populations of Artemia at increasing salinity conditions.

Material and Methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References
Cyst sampling

The cysts of the A. urmiana and of the parthenogenetic population were harvested in August 2008 from Lake Urmia and its coastal lagoons using plankton nets. The cysts were brought to the laboratory and after proper cleaning they were transferred into 4 L jars containing saturated brine (~280 g L−1) and incubated for a period of 15 days at room temperature. The cyst suspension was stirred thoroughly three times daily during this period. The cysts were then washed with brine water (150 g L−1) and kept in a freezer at −20°C for a period of 2 months to induce diapause deactivation. After this period, the cysts were stored at 4°C and used for hatching 1 week later [27].

Culture conditions

The cysts were hatched in 1 L glass cylindro-conical flasks filled with 800 mL diluted Lake Urmia water under standard conditions: 33 g L−1 salinity, 28 ± 0.5°C, pH: 8.0, light intensity ~2000 lux, with vigorous aeration for 24 h [34]. After hatching, the instar-I nauplii from each population were carefully counted and 6000 nauplii (1 ind mL−1) transferred directly into six cylindro-conical flasks containing 6 L of diluted water of Lake Urmia at a salinity of 150 g L−1. The salinity in half of the experimental flasks was gradually increased to 250 g L−1 at the rate of 10 g L−1 every alternate day. Water salinity at two experimental levels (150 and 250 g L−1) was kept constant by adding distilled water to compensate evaporation and to avoid stressing the animals during the experiment [35].

Three flasks at each salinity level were set up for each of the two Artemia populations and exposed to PAR (400–700 nm, 2000 lux) as control groups. In order to examine the effects of UV-B radiation, the experimental flasks containing Artemia were exposed to PAR+UV-B radiation (emitted by F8T5 UV-B 302 nm lamps; Japan) at a UV flux of 10 μW cm−2 (360 J m−2 h−1) and measured at 310 nm with a UVX-31 Radiometer (UVP, USA) [36]. Exposure to UV-B radiation was performed for 1 h day−1 from the first day after hatching (instar-I nauplii) until adulthood. Each treatment was performed with three replicates. The animals were fed once daily with a unicellular green algae, Dunaliella salina (150 × 103 cells mL−1), following the feeding schedule described by Coutteau et al. [37]. The temperature was kept constant at 28 ± 0.5°C, and mild aeration was applied from the bottom of the flasks throughout the experiment. The photoperiod (laboratory light) was set at 12:12 h light–dark condition by means of normal fluorescent light tubes (2000 lux).

The Artemia was harvested at the end of the culture period once they reached the adult stage. The animals were considered mature when males started to clasp females in the case of sexual A. urmiana or when signs of ovarian development and migration of the oocytes into the uterus were observed in the parthenogenetic females [35]. In the present study, the Artemia reached its adult stage from 14 to 23 days in culture at different salinities and radiations.

MAA analysis

After incubation in the different treatments, the surviving adult individuals for each population in all replicates were harvested, washed with distilled water and placed into 5 mL glass vials. They were immediately frozen at −80°C, lyophilized and stored at −80°C until the analyses of MAAs were performed.

Then 0.1 g of the lyophilized Artemia from each replicate was extracted sequentially in three extraction steps using 3, 2 and 1 mL of 100% HPLC grade methanol for 1 h, respectively. The samples were prepared using a glass-crusher (DELAWARE, 96006), during the extractions. After each extraction step, the contents were centrifuged at 1252 g for 20 min (4°C) to eliminate the remaining cellular debris and the supernatant was decanted and pooled. The pooled extract was then passed through a C-18 Sep-PakTM Plus cartridge (Waters Corp., Milford, MA) to remove lipids and other chromatographically intractable materials. Three aliquots were transferred into 1.5 mL Eppendorf tubes and the methanol was removed by freeze-drying. The dry extracts were stored at −80°C until the high-performance liquid chromatography (HPLC; Shimadzu System, Japan) analyses were performed [10, 38-41].

HPLC was used to identify and quantify the MAAs in the extracts. The dried extracts of Artemia were resuspended in 100 mL of 100% methanol and were left to stand at room temperature for 2 h with vortex mixing at 0.5 h intervals. The resuspended extracts were centrifuged at 1252 g to remove salts and other insoluble materials and then were sieved through a 100 kDa ultrafilter (Ultraspin). Samples were analyzed by HPLC as follows: individual MAAs were separated by reverse phase, and the gradient elution was performed on Alltima (Alltech) C18, 5 μm columns (4.6 mm i.d. × 150 mm length) protected with an Alltech guard column cartridge (4.6 mm i.d. × 20 mm length) filled with the same material [42]. They were connected in series and thermostated at 30°C. An initial isocratic hold until 8 min with 0.2 acetic acid was followed by a gradient with methanol:acetonitrile (0.2% acetic acid, 25:25:50) at a flow rate of 1.0 mL min−1. Peaks were detected using a diode array detector. Individual peaks were identified by online absorption spectra, retention time and chromatography with the prepared standards. Chemical identities of prepared standards were confirmed by alkaline hydrolysis and analysis of their amino acid composition using the method of Einarsson et al. [43] described in Carreto et al. [41]. The concentrations of MAAs were quantified using the molar extinction coefficients (ε) at the wavelengths of maximum absorption reported by previous studies [41, 42].

Statistical analysis

The results of the experiment were analyzed by means of two-way analysis of variance (ANOVA) using the software SPSSTM (ver. 15.0) to study the main effects and the interaction between salinity and UV-B radiation on the bioaccumulation of MAAs in A. urmiana and parthenogenetic Artemia at a confidence level of < 0.05 [44].

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Both Artemia showed a higher mortality at the salinity level of 250 g L−1. Mortality was even higher when high salinity along with UV-B radiation treatments was applied.

Seven known MAAs, with different concentrations, were identified: (1) Asterina-330 (AS, λmax = 330); (2) Shinorine (SH, λmax =  334); (3) Mycosporine-2glycine (Myc-2G, λmax = 334); (4) Palythine (PI, λmax = 320); (5) porphyra-334 (PR, λmax = 334); (6) Mycosporine-glycine:Valine (Myc-G:V, λmax = 335) and (7) Palythinol (PL, λmax = 332) (Fig. 1, upper and lower panels). Both Artemia populations contained the seven MAAs (Fig. 1, lower panel). The most abundant MAA was Mycosporine-2glycine, followed by Shinorine and Porphyra-334 in both populations (Fig. 1, lower panel).

image

Figure 1. Upper panel: Total mycosporine-like amino acid (MAA) concentrations (nmol g−1 dry weight). Lower panel: Relative contribution (%) of individual MAAs of the total MAAs in Artemia urmiana and parthenogenetic Artemia cultured under varying light and salinity conditions. Asterina-330 (AS), Palythinol (PL), Palythine (PI), Shinorine (SH), Mycosporine-2glycine (Myc-2G), Porphyra-334 (PR) and Mycosporine-glycine:Valine (Myc-G:V). The three former MAAs were detected at extremely low levels and are imperceptible in the figure.

Download figure to PowerPoint

A series of two-way ANOVA examined the effect of salinity and light on individual MAA concentrations. Both the salinity level and the light treatment had significant effects on the concentration of individual MAAs in Artemia, and the interaction between these main factors was significant (Table 1).

Table 1. Two-way ANOVA examining the effect of salinity (150 and 250 g L−1) and light source (PAR-only and PAR+UVR) on MAA concentrations in two Artemia strains from Lake Urmia and neighboring lagoons: Asterina-330 (AS), Palythinol (PL), Palythine (PI), Shinorine (SH), Mycosporine-2glycine (Myc-2G), Porphyra-334 (PR) and Mycosporine-glycine:Valine (Myc-G:V)
MAA identityd.f.ASSHMyc-2GPIPRMyc-G:VPL
SourceFFFFFFF
  1. Bold numbers show that P is <0.05 and significant difference is presence.

A. urmiana
Salinity (SA)19655.73616157.37123.54532.32710724.534.756.1.677
(0.000) (0.000) (0.001) (0.000) (0.000) (0.000) (0.231)
Light (LI)19479.781321.53332589.3905768.3562200.5486370.852220.595
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
SA × LI1495.556782.11034.0645.59839.76150.11216.917
(0.000) (0.000) (0.000) (0.046) (0.000) (0.000) (0.003)
Parthenogenetic
Artemia
Salinity (SA)110343.55626328.9586312.024693.3754741.8285635.392150.302
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
Light (LI)1792.00318132.861684.6642434.1322026.4951000.832687.335
(0.000) (0.000) (0.000) (0.000) (0.000) (0.000) (0.000)
SA × LI174.6129077.147163.076592.3407.41342.162107.613
(0.000) (0.000) (0.000) (0.000) (0.026) (0.000) (0.000)
Residual8       
Corrected total11       

A significantly greater amount of porphyra-334 was measured in the Artemia grown under PAR-only compared to PAR+UV-B at both salinities (Fig. 2 and Table 1). In other words, the bioaccumulation experiment showed that the amount of MAAs, except porphyra-334, increased significantly when the Artemia were exposed to PAR+UV-B at both salinities (Fig. 2 and Table 1). However, the concentration of Shinorine, at higher salinity level, was lower in the A. urmiana exposed to PAR+UV-B compared to those exposed to PAR alone (Fig. 2 and Table 1).

image

Figure 2. Concentrations of MAAs in Artemia urmiana and parthenogenetic Artemia cultured under either PAR or PAR+UVR light conditions at the two different salinities: (a) Asterina-330 (AS), Palythinol (PL) and Palythine (PI), (b) Shinorine (SH), Mycosporine-2glycine (Myc-2G), Porphyra-334 (PR) and Mycosporine-glycine:Valine (Myc-G:V). Values are mean ± SD.

Download figure to PowerPoint

Increased salinity under both PAR-only and PAR+UV-B resulted in higher levels of MAAs in both Artemia (Figs. 1 and 2). However, there were some exceptions and salinity increase could not induce MAA accumulations and even led to a decrease in the content of specific MAAs. For example, in A. urmiana, the concentration of Mycosporine-2glycine and Palythinol decreased with the increment of the salinity of the culture in PAR. A similar result was observed in the case of Mycosporine-glycine:Valine under PAR+UV-B.

Importantly, the exposure to the salinity level of 250 g L−1 and PAR+UV-B produced significantly higher concentrations of MAAs than when Artemia were under 150 g L−1 and PAR (Fig. 2 and Table 1). When exposed to PAR+UV-B, both Artemia showed significantly higher concentrations of MAAs at 250 g L−1 than at the lower salinity treatments.

In most cases, a significantly higher concentration of MAAs was found in the parthenogenetic Artemia compared to the sexual A. urmiana. As presented in Fig. 2, upper panel, this situation, however was reversed in favor of A. urmiana when they were cultured at 150 g L−1 under PAR+UV-B throughout the experiment. The analyses revealed that the concentration of Asterina-330, Mycosporine-2glycine and Palythine was higher in A. urmiana compared to parthenogenetic Artemia: When the animals were exposed to PAR+UV-B light at 150 g L−1, similar high concentrations of Mycosporine-glycine:Valine were detected in A. urmiana reared in the same salinity under both PAR and PAR+UV-B. However, significantly higher levels of Shinorine were found in A. urmiana cultured at 250 g L−1 under normal light (PAR-only), while higher concentrations of porphyra-334 were detected at the same salinity under both light sources (Fig. 2).

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

We studied the quantitative and qualitative composition of MAAs in two different Iranian populations of Artemia in different salinity and UV-B radiation conditions. Up to seven MAAs (Asterina-330, Shinorine, Mycosporine-2glycine, Palythine, porphyra-334, Mycosporine-glycine:Valine and Palythinol) were identified in the samples, with Mycosporine-2glycine and Shinorine being predominant. The presence of four major MAAs with maximum absorption level between 332 and 334 nm (Mycosporine-Gly:Ser, Mycosporine-Gly:Thr, Mycosporine-Gly:Alaninol and Mycosporine-Gly:Asp) was initially reported by Grant et al. [45] from decapsulated cysts of different strains of brine shrimp Artemia.

According to Oren [16], immediate excretion of intracellular MAAs by the unicellular cyanobacteria inhabiting in a hypersaline pond Eilat (Israel) following the sudden reduction in salinity of the external medium suggests the osmoregulatory role of MAAs.

Low-molecular-weight and uncharged organic molecules of MAAs [7, 8] may possibly contribute to their osmoregulatory function. The results obtained in our study suggest that higher concentrations of MAAs are accumulated under high salinity and UV-B exposure conditions. The concentration of Mycosporine-2glycine and Palythinol in A. urmiana declined by increasing salinity under PAR, while a similar trend was observed in the concentration of Mycosporine-glycine:Valine under exposure to PAR+UV-B.

Nevertheless, as documented earlier, if MAAs have a role in osmotic regulation, it could be negligible in the presence of major osmolytes like free amino acids (FAA) as proposed by Shick and Dunlap [7]. Taurine is one of the amino acids known to contribute in osmoregulation [46]. Furthermore, according to our measurements, the concentrations of MAAs in Artemia are much lower than that of taurine, which is known to be the dominant amino acid in the FAA pool of Artemia [47]. However, regarding the fact that known environmental stressors other than UV-B and osmotic stress do not affect MAA concentration [17], the relationship between intracellular MAAs and osmotic stress cannot be fully denied.

Temporal and spatial patterns in MAA concentrations, with high concentrations during periods of elevated environmental stress such as high levels of solar UV-B radiation suggest the photoprotective role of these compounds [10-13]. This argument supports our findings that the MAAs are accumulated in Artemia also as in other invertebrates in response to exposure to UV, confirming the findings by Pérez et al. [48] and Moeller et al. [13] on copepods.

Ultraviolet radiation seems to be the major factor inducing the accumulation of total MAAs in A. urmiana. The strongest factor in parthenogenetic Artemia, however, was the salinity (Fig. 1, upper panel), suggesting that accumulation of MAAs is triggered by providing UV-B radiation, but that its rate is controlled by salinity as well. These observations are consistent with the idea that A. urmiana is more resistant to high salinities than the parthenogenetic Artemia [27, 32].

Our results showed that, in most of the cases, the mean concentration of MAAs was higher in parthenogenetic Artemia compared to the sexual A. urmiana. As suggested earlier, the geographical separation of Artemia populations results in a number of different strains and species with various phenotypes and different biological, biochemical and physiological characteristics [49]. Therefore, one possible explanation for the differences in MAA concentration between Artemia populations may arise from the species-specific characteristics and selective accumulation of MAAs in various species. It has been suggested that absorption of MAAs occurs through a carrier-mediated mechanism and accordingly their selective accumulation can be due to the presence of specific transporters in the gut [7]. As in the present study obvious differences were found in bioaccumulation of MAAs between the two studied strains, though the experiments were performed under the same culture conditions, it may be assumed that genetic diversity possibly has a stronger role on the origin of these differences than habitat isolation.

Alternatively, we could assume that the other source of this difference might stem from different sexual composition and type of reproduction between the two Artemia communities tested. One significant point when evaluating these data is that the sampling period coincided with the maturation and release of eggs. In this regard, several previous observations indicated that the concentrations of individual MAAs in the ovaries of various marine invertebrates may reach their peak at the time of reproductive maturity [20-22, 50]. Besides, studies on different marine invertebrates revealed that MAA contents were higher in ovary and eggs than in other body tissues, such as gut, digestive gland, skin and particularly testis and sperms [20, 21, 50-53]. Therefore, high concentrations of MAAs in the parthenogenetic population of Artemia could be attributed in most cases to the sex-specific variation levels of MAAs in the studied populations. The population of parthenogenetic Artemia is mostly made up by female and a very small number of sterile males, while the sexual A. urmiana has a sex ratio of ca 1:1 [49].

Accordingly, it is concluded that certain level of MAAs was present as constitutive in Artemia, and a significant synergistic enhancement of MAA accumulation was observed when high salinity and UV levels were applied in combination. Thus, the presence of MAAs in this crustacean may enhance its potential to tolerate high UV and salinity conditions as those present in Lake Urmia.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

We thank Dr. Martine Fouchereau-Peron and Dr. Jose I. Carreto for their important collaboration. We also thank the technicians of Artemia and Aquatic Animals Research Institute of Urmia University laboratories for their assistance in this research. This research was financially supported by Artemia and Aquatic Animals Research Institute, Urmia University (Urmia, Iran) and the Department of Marine Biology of Tarbiat Modares University, Iran.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Material and Methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References
  • 1
    Franklin, L. A. and R. M. Forester (1997) The changing irradiance environment: Consequences for marine macrophyte physiology, productivity and ecology. Eur. J. Phycol. 32, 207232.
  • 2
    Kowenberg, J. H. M., H. I. Browman, J. A. Runge, J. J. Cullen, R. F. Davis and J. F. St. Pierre (1999) Biological weighting of ultraviolet (280–400 nm) induced mortality in marine zooplankton and fish. II. Calanus finmarchicus (Copepoda) eggs. Mar. Biol. 134, 285293.
  • 3
    Aarseth, K. A. and T. A. Schram (1999) Wavelength-specific behaviour in Lepeophtheirus salmonis and Calanus finmarchicus to ultraviolet and visible light in laboratory experiments (Crustacea: copepoda). Mar. Ecol. Prog. Ser. 186, 211217.
  • 4
    Adams, N. L. and J. M. Shick (2001) Mycosporine-like amino acids prevent UVB-induced abnormalities during early development of the green sea urchin Stronglyocentrotus droebachiensis. Mar. Biol. 138, 267280.
  • 5
    Helbling, E. W. and H. Zagarese (2003) UV Effects in Aquatic Organisms and Ecosystems. Royal Society of Chemistry, Cambridge, UK.
  • 6
    Naganuma, T. T. I. and S. Uye (1997) Photoreactivation of UV-induced damage to embryos of a planktonic copepod. J. Plankton Res. 19, 783787.
  • 7
    Shick, J. M. and W. C. Dunlap (2002) Mycosporine-like amino acids and related gadusols: Biosynthesis, accumulation, and UV-protective functions in aquatic organisms. Annu. Rev. Physiol. 64, 223262.
  • 8
    Singh, S. P., S. Kumari, R. P. Rastogi, K. L. Singh and R. P. Sinha (2008) Mycosporine-like amino acids (MAAs): Chemical structure, biosynthesis and significance as UV-absorbing/screening compounds. Indian J. Exp. Biol. 46, 717.
  • 9
    Karentz, D. (2001) Chemical defenses of marine organisms against solar radiation exposure: UV-absorbing mycosporine-like amino acids and scytonemin. In Marine Chemical Ecology (Edited by J. B. McClintock and B. J. Baker), pp. 481520. CRC Press, Boca Raton, FL.
  • 10
    Carreto, J. I. and O. Mario (2011) Carignan mycosporine-like amino acids: Relevant secondary metabolites. Chemical and ecological aspects. Mar. Drugs 9, 387446.
  • 11
    Tartarotti, B. and R. Sommaruga (2006) Seasonal and ontogenetic changes of mycosporine-like amino acids in planktonic organisms from an alpine lake. Limnol. Oceanogr. 51, 15301541.
  • 12
    Laurion, I., A. Lami and R. Sommaruga (2002) Distribution of mycosporine-like amino acids and photoprotective carotenoids among freshwater phytoplankton assemblages. Aquat. Microb. Ecol. 26, 283294.
  • 13
    Moeller, R. E., S. H. Gilroy, C. E. Williamson, G. Grad and R. Sommaruga (2005) Dietary acquisition of photoprotective compounds (mycosporine-like amino acids, carotenoids) and acclimation to ultraviolet radiation in a freshwater copepod. Limnol. Oceanogr. 50, 427439.
  • 14
    Arbeloa, E. M., M. J. Uez, S. G. Bertolotti and M. S. Churio (2010) Antioxidant activity of gadusol and occurrence in fish roes from Argentine Sea. Food Chem. 119, 586591.
  • 15
    Dunlap, W. C. and J. M. Shick (1998) Ultraviolet radiation-absorbing mycosporine-like amino acids in coral reef organisms: A biochemical and environmental perspective. J. Phycol. 34, 418430.
  • 16
    Oren, A. (1997) Mycosporine-like amino acids as osmotic solutes in a community of halophilic cyanobacteria. Geomicrobiol J. 14, 231240.
  • 17
    Portwich, A. and F. Garcia-Pichel (1999) Ultraviolet and osmotic stresses induce and regulate the synthesis of mycosporines in the cyanobacterium Chlorogloeopsis PCC 6912. Arch. Microbiol. 172, 187192.
  • 18
    Oren, A. and N. Gunde-Cimerman (2007) Mycosporines and mycosporine-like amino acids: UV protectants or multipurpose secondary metabolites? FEMS Microbiol. Lett. 269, 110.
  • 19
    Arpin, N. and M. L. Bouillant (1981) Light and mycosporines. In The Fungal Spore, Morphogenetic Controls (Edited by G. Turian and H. R. Hohl), pp. 159173. Academic Press, London, UK.
  • 20
    Bandaranayake, W. M., D. J. Bourne and R. G. Sim (1997) Chemical composition during maturing and spawning of the sponge Dysidea herbacea (Porifera: Demospongiae). Comp. Biochem. Physiol. 118B, 851859.
  • 21
    Bandaranayake, W. M. and A. Rocher (1999) Role of secondary metabolites and pigments in the epidermal tissues, ripe ovaries, viscera, gut contents and diet of the sea cucumber Holothuria atra. Mar. Biol. 133, 163169.
  • 22
    Adams, N. L., J. M. Shick and W. C. Dunlap (2001) Selective accumulation of mycosporine-like amino acids in ovaries of the green sea urchin Strongylocentrotus droebachiensis is not affected by ultraviolet radiation. Mar. Biol. 138, 281294.
  • 23
    Yoshiki, M., K. Tsuge, Y. Tsuruta, T. Yoshimura, K. Koganemaru, T. Sumi, T. Matsui and K. Matsumoto (2009) Production of new antioxidant compound from mycosporine-like amino acid, porphyra-334 by heat treatment. Food Chem. 113, 11271132.
  • 24
    Korbee Peinado, N., R. T. Abdala Díaz, F. L. Figueroa and E. W. Helbling (2004) Ammonium and UV radiation stimulate the accumulation of mycosporine-like amino acids in Porphyra columbina (Rhodophyta) from Patagonia, Argentina. J. Phycol. 40, 248259.
  • 25
    Kicklighter, C., M. Kamio, M. Gemann and C. Derby (2007) Pyrimidines and mycosporine-like amino acids function as alarm cues in the defensive secretions of the sea hare Aplysia californica. Chem. Senses, 32, A30.
  • 26
    Abatzopoulos, T. J., N. Agh, G. Van Stappen, S. M. Razavi Rouhani and P. Sorgeloos (2006) Artemia sites in Iran. J. Mar. Biol. Assoc. UK 86, 299307.
  • 27
    Agh, N., T. J. Abatzopoulos, I. Kappas, G. Van Stappen, S. M. Razavi Rouhani and P. Sorgeloos (2007) Coexistence of sexual and parthenogenetic Artemia populations in Lake Urmia and neighbouring Lagoons. Int. Rev. Hydrobiol. 92, 4860.
  • 28
    Post, F. J. and N. N. Youssef (1977) A prokaryotic intracellular symbiont of the Great Salt Lake brine shrimp Artemia salinia (L.). Can. J. Microbiol. 23, 12321236.
  • 29
    Bowen, S. T., M. R. Buoncristiani and J. R. Carl (1988) Artemia habitats: Ion concentrations tolerated by one superspecies. Hydrobiologia 158, 201214.
  • 30
    Azari Takami, G. (1993) Urmiah Lake as a valuable source of Artemia for feeding sturgeon fry. J. Vet. Fac. Univ. Tehran 47, 214.
  • 31
    Günther, R. T. (1899) Contributions to the geography of Lake Urmia and its neighbourhood. Geogr. J. 14, 504523.
  • 32
    Agh, N. and F. Noori (1997) Introduction of a parthenogenetic population of Artemia from lagoons around Urmia Lake and its morphological comparison with Artemia urmiana. Proceedings of the 1st Iranian Congress of Zoology, Tehran, Iran, 16 October 1997.
  • 33
    Agh, N., G. Van Stappen, P. Bossier, H. Sepehri, V. Lotfi, S. M. Razavi Rouhani and P. Sorgeloos (2008) Effects of salinity on survival, growth, reproductive and life span characteristics of Artemia populations from Urmia Lake and neighboring lagoons. Pak. J. Biol. Sci. 11, 164172.
  • 34
    Sorgeloos, P., P. Lavens, P. Léger, W. Tackaert and D. Versichele (1986) Manual for the Culture and Use of Brine Shrimp Artemia in Aquaculture. State University of Ghent, Ghent, Belgium.
  • 35
    Triantaphyllidis, G. V., K. Poulopoulou, T. J. Abatzopoulos, C. A. Pinto Perez and P. Sorgeloos (1995) International study on Artemia XLIX. Salinity effects on survival, maturity, growth, biometrics, reproductive and lifespan characteristics of a bisexual and a parthenogenetic population of Artemia. Hydrobiologia 302, 215227.
  • 36
    Ghanizadeh Kazerouni, E. and S. Khodabandeh (2010) Effects of ultraviolet radiation on skin structure and ultrastructure in the Caspian Sea Salmon, Salmo trutta caspius, during alevin stage. Toxicol. Environ. Chem. 92, 903914.
  • 37
    Coutteau, P., L. Brendonck, P. Lavens and P. Sorgeloos (1992) The use of manipulated baker's yeast as an algal substitute for the laboratory culture of Anostraca. Hydrobiologia 234, 2532.
  • 38
    Rastogi, R. P., R. P. Sinha, S. P. Singh and D. P. Häder (2010) Photoprotective compounds from marine organisms. J. Ind. Microbiol. Biotechnol. 37, 537558.
  • 39
    Arbeloa, E. M., M. O. Carignan, F. H. Acuña, M. S. Churio and J. I. Carreto (2010) Mycosporine-like amino acid content in the sea anemones Aulactinia marplatensis, Oulactis muscosa and Anthothoe chilensis. Comp. Biochem. Physiol. B, 156, 216221.
  • 40
    Cardozo, K. H. M., L. G. Marques, V. M. Carvalho, M. O. Carignan, E. Pinto, E. Marinho-Soriano and P. Colepicolo (2011) Analyses of photoprotective compounds in red algae from the Brazilian coast. Braz. J. Pharmacogn. 21, 202208.
  • 41
    Carreto, J. I., M. O. Carignan and N. G. Montoya (2001) Comparative studies on mycosporine-like amino acids, paralytic shellfish toxins and pigment profiles of the toxic dinoflagellates Alexandrium tamarense, A. catenella and A. minutum. Mar. Ecol. Prog. Ser. 223, 4960.
  • 42
    Bandaranayake, W. M. (1998) Mycosporines: Are they nature's sunscreens? Natural product reports. R. Soc. Chem. Spec. Publ. 15, 159173.
  • 43
    Einarsson, S., S. Folestad, B. Josefsson and S. Lagerkvist (1986) High-resolution reversed-phase liquid chromatography system for the analysis of complex solutions of primary and secondary amino acids. Anal. Chem. 58, 16381643.
  • 44
    Zar, J. H. (1998) Biostatistical Analysis. Prentice-Hall Inc., Upper Saddle River, NJ.
  • 45
    Grant, P. T., C. Middleton, P. A. Plack and R. A. Thomson (1985) The isolation of four aminocyclohexenimines (mycosporines) and a structurally related derivative of cyclohexane-1:3-dione (gadusol) from the brine shrimp, Artemia. Comp. Biochem. Physiol. 80, 755759.
  • 46
    Huxtable, R. J. (1992) Physiological actions of taurine. Physiol. Rev. 72, 101163.
  • 47
    Aragăo, C., L. E. C. Conceiçăo, M. T. Dinis and H.-J. Fyhn (2004) Amino acid pools of rotifers and Artemia under different conditions: nutritional implications for fish larvae. Aquaculture 234, 429445.
  • 48
    Pérez, P., D. Libkind, M. Del Carmen Diéguez, M. Summerer, B. Sonntag, R. Sommaruga, M. Van Broock and H. E. Zagarese (2005) Mycosporines from freshwater yeasts: A trophic cul-de-sac? Photochem. Photobiol. Sci. 5, 2530.
  • 49
    Triantaphyllidis, G. V., T. J. Abatzopoulos and P. Sorgeloos (1998) Review of the biogeography of the genus Artemia (Crustacea, Anostraca). J. Biogeogr. 25, 213226.
  • 50
    Carroll, A. K. and J. M. Shick (1996) Dietary accumulation of UV-absorbing mycosporine-like amino acids (MAAs) by the green sea urchin (Strongylocentrotus droebachiensis). Mar. Biol. 124, 561569.
  • 51
    Karentz, D., I. Bosch and W. C. Dunlap (1992) Distribution of UV-absorbing compounds in the antarctic limpet, Nacella concinna. Antarct. J. U.S. 27, 121122.
  • 52
    Adams, N. L. and J. M. Shick (1996) Mycosporine-like amino acids provide protection against ultraviolet radiation in eggs of the green sea urchin, Strongylocentrotus droebachiensis. Photochem. Photobiol. 64, 149158.
  • 53
    Carefoot, T. H., D. Karentz, S. C. Pennings and C. L. Young (2000) Distribution of mycosporine-like amino acids in the sea hare Aplysia dactylomela: Effect of diet on amounts and types sequestered over time in tissues and spawn. Comp. Biochem. Phys. C. 126, 91104.