INVESTIGADORES
FERREYRA Gustavo Adolfo
artículos
Título:
Comparative study of defense strategies against UV-induced damage in an Antarctic diatom (Thalassiosira sp.) and a Sub-Antarctic phytoflagellate (Asteromonas sp.)
Autor/es:
HERNANDO, M., G. MALANGA, S. PUNTARULO AND G.A. FERREYRA
Revista:
Reports on Polar and Marine Research
Referencias:
Año: 2008 vol. 571 p. 243 - 253
Resumen:
During the past decades, spring-time stratospheric ozone depletion over the
Antarctic and the Southern Ocean has resulted in enhanced levels of ultraviolet-
B (UVB, 280-315 nm) radiation reaching the earth´s surface. One of the main
difficulties to evaluate the potential ecological impact on natural phytoplankton
of increased in UVB is that UV sensitivity is species specific (Hernando & San
Román 1999; Hernando 2006). UVR induced effects on phytoplankton include
the reduction of growth and photosynthetic rates (Villafañe et al., 2003). Some
studies have demonstrated that the of ultraviolet-A (UVA, 315 400 nm) were
generally higher than that of UVB (Villafañe et al., 2003). This is generally
attributed to the fact that the amount of UVA energy that reaches the Earths
surface is much higher than that in the UVBR region (Villafañe et al., 1999).
Several biological effects of UVB involve endogenous photosensitization and
formation of reactive oxygen species (Martin & Burch 1990). There are a variety
of sensitizers within cells which absorb UVB. Interaction between excited sensitizers
and triplet oxygen produces active oxygen intermediates consisting of
singlet oxygen (1O2), superoxide radical (O2
-), hydroxyl radical (.OH) and hydrogen
peroxide (H2O2) (Ichiki et al. 1994). One of the possible mechanisms that
could counteract the damage generated by UVB radiation induced oxidative
stress is the synthesis of both enzymatic and non-enzymatic antioxidants
(Davidson 1998; Niyogi 1999). Moreover UVB can destroy the natural lipid
soluble antioxidants and promote the formation of lipid peroxidation products
(Estévez et al. 2001). The non-enzymatic antioxidants are generally small
molecules, such as ascorbate and glutathione acting in the aqueous phase,
whereas the lipophilic antioxidants (such as -tocopherol and -carotene) are
active in the membrane environment. Especially -tocopherol is known for its
protective effect against lipid peroxidation of biological membranes via peroxyl
and alcoxyl radicals scavenging. In contrast, the main function of -carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.1O2), superoxide radical (O2
-), hydroxyl radical (.OH) and hydrogen
peroxide (H2O2) (Ichiki et al. 1994). One of the possible mechanisms that
could counteract the damage generated by UVB radiation induced oxidative
stress is the synthesis of both enzymatic and non-enzymatic antioxidants
(Davidson 1998; Niyogi 1999). Moreover UVB can destroy the natural lipid
soluble antioxidants and promote the formation of lipid peroxidation products
(Estévez et al. 2001). The non-enzymatic antioxidants are generally small
molecules, such as ascorbate and glutathione acting in the aqueous phase,
whereas the lipophilic antioxidants (such as -tocopherol and -carotene) are
active in the membrane environment. Especially -tocopherol is known for its
protective effect against lipid peroxidation of biological membranes via peroxyl
and alcoxyl radicals scavenging. In contrast, the main function of -carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.), hydroxyl radical (.OH) and hydrogen
peroxide (H2O2) (Ichiki et al. 1994). One of the possible mechanisms that
could counteract the damage generated by UVB radiation induced oxidative
stress is the synthesis of both enzymatic and non-enzymatic antioxidants
(Davidson 1998; Niyogi 1999). Moreover UVB can destroy the natural lipid
soluble antioxidants and promote the formation of lipid peroxidation products
(Estévez et al. 2001). The non-enzymatic antioxidants are generally small
molecules, such as ascorbate and glutathione acting in the aqueous phase,
whereas the lipophilic antioxidants (such as -tocopherol and -carotene) are
active in the membrane environment. Especially -tocopherol is known for its
protective effect against lipid peroxidation of biological membranes via peroxyl
and alcoxyl radicals scavenging. In contrast, the main function of -carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.2O2) (Ichiki et al. 1994). One of the possible mechanisms that
could counteract the damage generated by UVB radiation induced oxidative
stress is the synthesis of both enzymatic and non-enzymatic antioxidants
(Davidson 1998; Niyogi 1999). Moreover UVB can destroy the natural lipid
soluble antioxidants and promote the formation of lipid peroxidation products
(Estévez et al. 2001). The non-enzymatic antioxidants are generally small
molecules, such as ascorbate and glutathione acting in the aqueous phase,
whereas the lipophilic antioxidants (such as -tocopherol and -carotene) are
active in the membrane environment. Especially -tocopherol is known for its
protective effect against lipid peroxidation of biological membranes via peroxyl
and alcoxyl radicals scavenging. In contrast, the main function of -carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.-tocopherol and -carotene) are
active in the membrane environment. Especially -tocopherol is known for its
protective effect against lipid peroxidation of biological membranes via peroxyl
and alcoxyl radicals scavenging. In contrast, the main function of -carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.-tocopherol is known for its
protective effect against lipid peroxidation of biological membranes via peroxyl
and alcoxyl radicals scavenging. In contrast, the main function of -carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.-carotene is
photoreceptive, because it acts as a pigment antenna in the photosynthesis
process.
Another strategy to minimize the effects of UVR (ultraviolet radiation) is through
the presence of UV screening compounds. The most studied compounds are
those collectively named mycosporine like amino acids (MAAs), which are
found in many marine and freshwater algae (Karentz et al. 1991; Banaszak
2003). MAAs have been proved to be an effective protection mechanism (Neale
et al. 1998). The synthesis of MAAs was found in some natural populations and
cultures of phytoplankton (Hernando et al. 2002; Zudaire & Roy 2001). How
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
ever, the synthesis of MAA´s is not a general response, and several species do
not show an increase of MAAs content even after several weeks of exposure to
UVR (Villafañe et al. 2000).
The aim of this work was to study immediate effects on growth rate and photoprotection
parameters in response to UVB and UVA on a Sub-Antarctic phytoflagellate
(Asteromonas sp.) and an Antarctic diatom (Thalassiosira sp.) under
culture conditions.
culture conditions.