TY  - JOUR
AU  - Vojvodić, Snežana
AU  - Dimitrijević, Milena
AU  - Žižić, Milan
AU  - Dučić, Tanja
AU  - AQUILANTI, Giuliana
AU  - Stanić, Marina
AU  - Zechmann, Bernd
AU  - Danilović Luković, Jelena
AU  - Stanković, Dalibor M.
AU  - Opačić, Miloš
AU  - Morina, Arian
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2023
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2378
AB  - Metabolism of metals in microalgae and adaptation to metal excess are of significant environmental importance. We report a three-step mechanism that the green microalga Chlorella sorokiniana activates during the acquisition of and adaptation to manganese (Mn), which is both an essential trace metal and a pollutant of waters. In the early stage, Mn2+ was mainly bound to membrane phospholipids and phosphates in released mucilage. The outer cell wall
was reorganized and lipids were accumulated, with a relative increase in lipid saturation. Intracellular redox settings were rapidly altered in the presence of Mn excess, with increased production of reactive oxygen species that resulted in lipid peroxidation and a decrease in the concentration of thiols. In the later stage, Mn2+ was chelated by polyphosphates and accumulated in the cells. The structure of the inner cell wall was modified and the redox milieu established a new balance. Polyphosphates serve as a transient Mn2+ storage ligand, as proposed previously. In the final stage, Mn was stored in multivalent Mn clusters that resemble the structure of the tetramanganese–calcium core of the oxygen-evolving complex. The present findings elucidate the bioinorganic chemistry and metabolism of Mn in microalgae, and may shed new light on water-splitting Mn clusters.
PB  - Oxford University Press
T2  - Journal of Experimental Botany
T1  - A three-step process of manganese acquisition and storage in the microalga Chlorella sorokiniana
EP  - 1122
IS  - 3
SP  - 1107
VL  - 74
DO  - 10.1093/jxb/erac472
ER  - 

@article{
author = "Vojvodić, Snežana and Dimitrijević, Milena and Žižić, Milan and Dučić, Tanja and AQUILANTI, Giuliana and Stanić, Marina and Zechmann, Bernd and Danilović Luković, Jelena and Stanković, Dalibor M. and Opačić, Miloš and Morina, Arian and Pittman, Jon K. and Spasojević, Ivan",
year = "2023",
abstract = "Metabolism of metals in microalgae and adaptation to metal excess are of significant environmental importance. We report a three-step mechanism that the green microalga Chlorella sorokiniana activates during the acquisition of and adaptation to manganese (Mn), which is both an essential trace metal and a pollutant of waters. In the early stage, Mn2+ was mainly bound to membrane phospholipids and phosphates in released mucilage. The outer cell wall
was reorganized and lipids were accumulated, with a relative increase in lipid saturation. Intracellular redox settings were rapidly altered in the presence of Mn excess, with increased production of reactive oxygen species that resulted in lipid peroxidation and a decrease in the concentration of thiols. In the later stage, Mn2+ was chelated by polyphosphates and accumulated in the cells. The structure of the inner cell wall was modified and the redox milieu established a new balance. Polyphosphates serve as a transient Mn2+ storage ligand, as proposed previously. In the final stage, Mn was stored in multivalent Mn clusters that resemble the structure of the tetramanganese–calcium core of the oxygen-evolving complex. The present findings elucidate the bioinorganic chemistry and metabolism of Mn in microalgae, and may shed new light on water-splitting Mn clusters.",
publisher = "Oxford University Press",
journal = "Journal of Experimental Botany",
title = "A three-step process of manganese acquisition and storage in the microalga Chlorella sorokiniana",
pages = "1122-1107",
number = "3",
volume = "74",
doi = "10.1093/jxb/erac472"
}

Vojvodić, S., Dimitrijević, M., Žižić, M., Dučić, T., AQUILANTI, G., Stanić, M., Zechmann, B., Danilović Luković, J., Stanković, D. M., Opačić, M., Morina, A., Pittman, J. K.,& Spasojević, I.. (2023). A three-step process of manganese acquisition and storage in the microalga Chlorella sorokiniana. in Journal of Experimental Botany
Oxford University Press., 74(3), 1107-1122.
https://doi.org/10.1093/jxb/erac472

Vojvodić S, Dimitrijević M, Žižić M, Dučić T, AQUILANTI G, Stanić M, Zechmann B, Danilović Luković J, Stanković DM, Opačić M, Morina A, Pittman JK, Spasojević I. A three-step process of manganese acquisition and storage in the microalga Chlorella sorokiniana. in Journal of Experimental Botany. 2023;74(3):1107-1122.
doi:10.1093/jxb/erac472 .

Vojvodić, Snežana, Dimitrijević, Milena, Žižić, Milan, Dučić, Tanja, AQUILANTI, Giuliana, Stanić, Marina, Zechmann, Bernd, Danilović Luković, Jelena, Stanković, Dalibor M., Opačić, Miloš, Morina, Arian, Pittman, Jon K., Spasojević, Ivan, "A three-step process of manganese acquisition and storage in the microalga Chlorella sorokiniana" in Journal of Experimental Botany, 74, no. 3 (2023):1107-1122,
https://doi.org/10.1093/jxb/erac472 . .

TY  - CONF
AU  - Santrač, Isidora
AU  - Danilović Luković, Jelena
AU  - Dimitrijević, Milena
AU  - Stanić, Marina
AU  - Tanović, Marija
AU  - Ćurić, Valentina
AU  - Kovačević, Snežana
AU  - Zechmann, Bernd
AU  - Žižić, Milan
AU  - Spasojević, Ivan
PY  - 2023
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/3144
AB  - Haematococcus pluvialis is a unicellular green alga with a complex life cycle and a
remarkable metabolic and structural adaptability that allows it to thrive in metal-infested
environments. H. pluvialis could be potentially used in the remediation of waters polluted
with metals, such as manganese (Mn). Mn is also an essential element involved in different
metabolic processes, such as photosynthesis and antioxidantive defence. Herein, we
examined morphological response of metabolically active green cell type of H. pluvialis
(microzooids) to high Mn concentrations exceeding their physiological quota. When exposed
to 1 mM Mn2+, cell viability remained stable over a 3-day period. Inductively coupled plasma
atomic emission spectroscopy showed the prompt uptake of Mn by the microzooid cells after
1 h of the treatment, with a modest increase of the concentration of Mn in the biomass at 24
h. Scanning electron microscopy revealed granular deposits on microzooid surfaces after 1
hour, likely Mn deposits, while transmission electron microscopy (TEM) micrographs
showed that some cells had wall rupture and degraded intracellular content and damaged
organelles. After 24 and 72 h, a different type of cell morphology emerged, characterized by
thickened cell wall, preserved intracellular compartments, and reduced total area of lipid
droplets. Both cell types exhibited vacuoles containing dark granules, possibly indicative of
Mn accumulations. Quantitative TEM analysis demonstrated that an excess of Mn reduced
cell cross-section and lipid droplet area while increasing vacuole cross-section and cell wall
thickness. The intricate adaptive responses of H. pluvialis to elevated Mn concentrations
exemplified by cell wall thickening, reduction in lipid droplets total area due to increased
energy demand, and the accumulation of Mn in vacuoles, exhibits the impressive structural
adaptability. Further investigation using analytical methods will provide a more profound
understanding of the metabolic dimensions of adaptive response
PB  - UNIVERSITY OF BELGRADE, FACULTY OF TECHNOLOGY AND METALLURGY Karnegijeva 4, Belgrade
C3  - International Conference on Biochemical Engineering and Biotechnology for Young Scientists, December 7-8th 2023, Belgrade, Serbia
T1  - Structural adaptibility of Haematococcus pluvialis green phase cells exposed to manganese excess
EP  - 44
SP  - 44
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_3144
ER  - 

@conference{
author = "Santrač, Isidora and Danilović Luković, Jelena and Dimitrijević, Milena and Stanić, Marina and Tanović, Marija and Ćurić, Valentina and Kovačević, Snežana and Zechmann, Bernd and Žižić, Milan and Spasojević, Ivan",
year = "2023",
abstract = "Haematococcus pluvialis is a unicellular green alga with a complex life cycle and a
remarkable metabolic and structural adaptability that allows it to thrive in metal-infested
environments. H. pluvialis could be potentially used in the remediation of waters polluted
with metals, such as manganese (Mn). Mn is also an essential element involved in different
metabolic processes, such as photosynthesis and antioxidantive defence. Herein, we
examined morphological response of metabolically active green cell type of H. pluvialis
(microzooids) to high Mn concentrations exceeding their physiological quota. When exposed
to 1 mM Mn2+, cell viability remained stable over a 3-day period. Inductively coupled plasma
atomic emission spectroscopy showed the prompt uptake of Mn by the microzooid cells after
1 h of the treatment, with a modest increase of the concentration of Mn in the biomass at 24
h. Scanning electron microscopy revealed granular deposits on microzooid surfaces after 1
hour, likely Mn deposits, while transmission electron microscopy (TEM) micrographs
showed that some cells had wall rupture and degraded intracellular content and damaged
organelles. After 24 and 72 h, a different type of cell morphology emerged, characterized by
thickened cell wall, preserved intracellular compartments, and reduced total area of lipid
droplets. Both cell types exhibited vacuoles containing dark granules, possibly indicative of
Mn accumulations. Quantitative TEM analysis demonstrated that an excess of Mn reduced
cell cross-section and lipid droplet area while increasing vacuole cross-section and cell wall
thickness. The intricate adaptive responses of H. pluvialis to elevated Mn concentrations
exemplified by cell wall thickening, reduction in lipid droplets total area due to increased
energy demand, and the accumulation of Mn in vacuoles, exhibits the impressive structural
adaptability. Further investigation using analytical methods will provide a more profound
understanding of the metabolic dimensions of adaptive response",
publisher = "UNIVERSITY OF BELGRADE, FACULTY OF TECHNOLOGY AND METALLURGY Karnegijeva 4, Belgrade",
journal = "International Conference on Biochemical Engineering and Biotechnology for Young Scientists, December 7-8th 2023, Belgrade, Serbia",
title = "Structural adaptibility of Haematococcus pluvialis green phase cells exposed to manganese excess",
pages = "44-44",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_3144"
}

Santrač, I., Danilović Luković, J., Dimitrijević, M., Stanić, M., Tanović, M., Ćurić, V., Kovačević, S., Zechmann, B., Žižić, M.,& Spasojević, I.. (2023). Structural adaptibility of Haematococcus pluvialis green phase cells exposed to manganese excess. in International Conference on Biochemical Engineering and Biotechnology for Young Scientists, December 7-8th 2023, Belgrade, Serbia
UNIVERSITY OF BELGRADE, FACULTY OF TECHNOLOGY AND METALLURGY Karnegijeva 4, Belgrade., 44-44.
https://hdl.handle.net/21.15107/rcub_rimsi_3144

Santrač I, Danilović Luković J, Dimitrijević M, Stanić M, Tanović M, Ćurić V, Kovačević S, Zechmann B, Žižić M, Spasojević I. Structural adaptibility of Haematococcus pluvialis green phase cells exposed to manganese excess. in International Conference on Biochemical Engineering and Biotechnology for Young Scientists, December 7-8th 2023, Belgrade, Serbia. 2023;:44-44.
https://hdl.handle.net/21.15107/rcub_rimsi_3144 .

Santrač, Isidora, Danilović Luković, Jelena, Dimitrijević, Milena, Stanić, Marina, Tanović, Marija, Ćurić, Valentina, Kovačević, Snežana, Zechmann, Bernd, Žižić, Milan, Spasojević, Ivan, "Structural adaptibility of Haematococcus pluvialis green phase cells exposed to manganese excess" in International Conference on Biochemical Engineering and Biotechnology for Young Scientists, December 7-8th 2023, Belgrade, Serbia (2023):44-44,
https://hdl.handle.net/21.15107/rcub_rimsi_3144 .

TY  - CONF
AU  - Vojvodić, Snežana
AU  - Stanić, Marina
AU  - Danilović Luković, Jelena
AU  - Milivojević, Marija
AU  - Zechmann, Bernd
AU  - Dimitrijević, Milena
AU  - Opačić, Miloš
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2022
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2403
AB  - METHODS
The impact of a set of concentrations of Mn2+ and Ni2+ on growth of C. sorokiniana culture in 3N-BBM+V
medium in the early stationary phase was evaluated by changes in optical density at 750 nm and biomass
during 7 days treatment. Mucilage release was analyzed using SEM microscopy. Redox settings were analyzed
by oxidation-sensitive fluorescent probe and assays for thiols.
RESULTS
Ni was more toxic than Mn and affected culture growth at lower concentrations. Microalgal cells started
releasing mucilage polymers within 1 h of exposure to 1 mM Mn2+, whereas no mucilage was observed even
at 24 h of treatment with equimolar Ni2+. The peak of reactive oxygen species production was reached faster
for Ni2+ than Mn2+. Mn-induced drops in the concentration of reduced thiols showed a recovery after 1 h and
24 h. Ni2+-induced drop was irreversible. The observed differences between the impact of Mn and Ni may be
related to different redox and coordinative properties and to higher capacities of microalgae to sequester Mn
in relation to higher quotas than Ni that are required for normal functio
C3  - FEMS Conference on Microbiology (in association with Serbian Society of Microbiology), Belgrade, Serbia.
T1  - Comparative impact of Mn2+ and Ni2+ on the microalga Chlorella sorokiniana
EP  - 748
SP  - 747
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2403
ER  - 

@conference{
author = "Vojvodić, Snežana and Stanić, Marina and Danilović Luković, Jelena and Milivojević, Marija and Zechmann, Bernd and Dimitrijević, Milena and Opačić, Miloš and Pittman, Jon K. and Spasojević, Ivan",
year = "2022",
abstract = "METHODS
The impact of a set of concentrations of Mn2+ and Ni2+ on growth of C. sorokiniana culture in 3N-BBM+V
medium in the early stationary phase was evaluated by changes in optical density at 750 nm and biomass
during 7 days treatment. Mucilage release was analyzed using SEM microscopy. Redox settings were analyzed
by oxidation-sensitive fluorescent probe and assays for thiols.
RESULTS
Ni was more toxic than Mn and affected culture growth at lower concentrations. Microalgal cells started
releasing mucilage polymers within 1 h of exposure to 1 mM Mn2+, whereas no mucilage was observed even
at 24 h of treatment with equimolar Ni2+. The peak of reactive oxygen species production was reached faster
for Ni2+ than Mn2+. Mn-induced drops in the concentration of reduced thiols showed a recovery after 1 h and
24 h. Ni2+-induced drop was irreversible. The observed differences between the impact of Mn and Ni may be
related to different redox and coordinative properties and to higher capacities of microalgae to sequester Mn
in relation to higher quotas than Ni that are required for normal functio",
journal = "FEMS Conference on Microbiology (in association with Serbian Society of Microbiology), Belgrade, Serbia.",
title = "Comparative impact of Mn2+ and Ni2+ on the microalga Chlorella sorokiniana",
pages = "748-747",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2403"
}

Vojvodić, S., Stanić, M., Danilović Luković, J., Milivojević, M., Zechmann, B., Dimitrijević, M., Opačić, M., Pittman, J. K.,& Spasojević, I.. (2022). Comparative impact of Mn2+ and Ni2+ on the microalga Chlorella sorokiniana. in FEMS Conference on Microbiology (in association with Serbian Society of Microbiology), Belgrade, Serbia., 747-748.
https://hdl.handle.net/21.15107/rcub_rimsi_2403

Vojvodić S, Stanić M, Danilović Luković J, Milivojević M, Zechmann B, Dimitrijević M, Opačić M, Pittman JK, Spasojević I. Comparative impact of Mn2+ and Ni2+ on the microalga Chlorella sorokiniana. in FEMS Conference on Microbiology (in association with Serbian Society of Microbiology), Belgrade, Serbia.. 2022;:747-748.
https://hdl.handle.net/21.15107/rcub_rimsi_2403 .

Vojvodić, Snežana, Stanić, Marina, Danilović Luković, Jelena, Milivojević, Marija, Zechmann, Bernd, Dimitrijević, Milena, Opačić, Miloš, Pittman, Jon K., Spasojević, Ivan, "Comparative impact of Mn2+ and Ni2+ on the microalga Chlorella sorokiniana" in FEMS Conference on Microbiology (in association with Serbian Society of Microbiology), Belgrade, Serbia. (2022):747-748,
https://hdl.handle.net/21.15107/rcub_rimsi_2403 .

TY  - CONF
AU  - Vojvodić, Snežana
AU  - Stanić, Marina
AU  - Zechmann, Bernd
AU  - Dimitrijević, Milena
AU  - Opačić, Miloš
AU  - Danilović Luković, Jelena
AU  - Morina, Arian
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2420
AB  - Many neutrophilic and acidophilic microalgal species tolerate high metal concentrations
and can survive or colonize metal-polluted waters. They show significant biotechnological
potential for the remediation and wastewaters processing. On the other hand, negative effects
of metal pollution on microalgae may affect the function of aquatic ecosystems because these
photosynthetic microorganisms represent the primary producers of O2 and biomass. However,
adaptive mechanisms that microalgae employ to detoxify metal excess are largely unknown.
Herein we analyzed the response of the freshwater microalga Chlorella sorokiniana to high
but non-toxic levels of Mn2+. Manganese is a key metal pollutant, with five possible oxidation
forms that can bind to a variety of different ligands. At pH below 7, it is predominantly present in
Mn2+ form. Scanning electron microscopy showed that in response to 1 mM Mn2+, C. sorokiniana
released mucilage polymers within 1 h. Electron paramagnetic resonance spectroscopy (EPR)
showed that the early response involved loose Mn2+ binding to mucilage and/or the cell wall.
The amount of loosely bound Mn2+ was significantly decreased after 24 h, whereas biomass
showed significant accumulation of Mn, O and P, as determined by energy dispersive X-ray
spectrometry, indicating the production of polyphosphates, which may sequester Mn. Further,
it was found that the exposure to Mn2+ resulted in rapid and transient decrease of total free
glutathione concentration; the drop was observed after 1 h, and the concentration returned to
initial values after 24 h. EPR measurements showed a similar trend in the level of reduced thiols.
The observed changes can be explained either by the synthesis of phytochelatins – sulfurrich
short-chain peptides that sequester metals, or by glutathionylation of proteins. Reduced
thiols could not be detected in the extracellular space, indicating that C. sorokiniana did not
release thiols in response to high Mn. These results demonstrate that the adaptive response
of C. sorokiniana to high Mn levels involves multiple components and time phases. The early
phase involves mucilage release, phytochelatins and/or protection of protein thiols, whereas
the successive phase involves Mn coordination by polyphosphates and other mechanisms that
remain to be resolved.
PB  - Elsevier
PB  - Society for Free Radical Research Europe (SFRR-E)
PB  - Ministry of Education, Science and Technological Development (Republic of Serbia)
PB  - Oxygen Club of California
C3  - Redox Biology in the 21st Century: A New Scientific Discipline, Meeting Abstracts
T1  - Mechanisms of detoxification of high manganese concentrations by the microalga Chlorella sorokiniana
EP  - 145
SP  - 145
DO  - 10.1016/j.freeradbiomed.2021.08.148
ER  - 

@conference{
author = "Vojvodić, Snežana and Stanić, Marina and Zechmann, Bernd and Dimitrijević, Milena and Opačić, Miloš and Danilović Luković, Jelena and Morina, Arian and Pittman, Jon K. and Spasojević, Ivan",
year = "2021",
abstract = "Many neutrophilic and acidophilic microalgal species tolerate high metal concentrations
and can survive or colonize metal-polluted waters. They show significant biotechnological
potential for the remediation and wastewaters processing. On the other hand, negative effects
of metal pollution on microalgae may affect the function of aquatic ecosystems because these
photosynthetic microorganisms represent the primary producers of O2 and biomass. However,
adaptive mechanisms that microalgae employ to detoxify metal excess are largely unknown.
Herein we analyzed the response of the freshwater microalga Chlorella sorokiniana to high
but non-toxic levels of Mn2+. Manganese is a key metal pollutant, with five possible oxidation
forms that can bind to a variety of different ligands. At pH below 7, it is predominantly present in
Mn2+ form. Scanning electron microscopy showed that in response to 1 mM Mn2+, C. sorokiniana
released mucilage polymers within 1 h. Electron paramagnetic resonance spectroscopy (EPR)
showed that the early response involved loose Mn2+ binding to mucilage and/or the cell wall.
The amount of loosely bound Mn2+ was significantly decreased after 24 h, whereas biomass
showed significant accumulation of Mn, O and P, as determined by energy dispersive X-ray
spectrometry, indicating the production of polyphosphates, which may sequester Mn. Further,
it was found that the exposure to Mn2+ resulted in rapid and transient decrease of total free
glutathione concentration; the drop was observed after 1 h, and the concentration returned to
initial values after 24 h. EPR measurements showed a similar trend in the level of reduced thiols.
The observed changes can be explained either by the synthesis of phytochelatins – sulfurrich
short-chain peptides that sequester metals, or by glutathionylation of proteins. Reduced
thiols could not be detected in the extracellular space, indicating that C. sorokiniana did not
release thiols in response to high Mn. These results demonstrate that the adaptive response
of C. sorokiniana to high Mn levels involves multiple components and time phases. The early
phase involves mucilage release, phytochelatins and/or protection of protein thiols, whereas
the successive phase involves Mn coordination by polyphosphates and other mechanisms that
remain to be resolved.",
publisher = "Elsevier, Society for Free Radical Research Europe (SFRR-E), Ministry of Education, Science and Technological Development (Republic of Serbia), Oxygen Club of California",
journal = "Redox Biology in the 21st Century: A New Scientific Discipline, Meeting Abstracts",
title = "Mechanisms of detoxification of high manganese concentrations by the microalga Chlorella sorokiniana",
pages = "145-145",
doi = "10.1016/j.freeradbiomed.2021.08.148"
}

Vojvodić, S., Stanić, M., Zechmann, B., Dimitrijević, M., Opačić, M., Danilović Luković, J., Morina, A., Pittman, J. K.,& Spasojević, I.. (2021). Mechanisms of detoxification of high manganese concentrations by the microalga Chlorella sorokiniana. in Redox Biology in the 21st Century: A New Scientific Discipline, Meeting Abstracts
Elsevier., 145-145.
https://doi.org/10.1016/j.freeradbiomed.2021.08.148

Vojvodić S, Stanić M, Zechmann B, Dimitrijević M, Opačić M, Danilović Luković J, Morina A, Pittman JK, Spasojević I. Mechanisms of detoxification of high manganese concentrations by the microalga Chlorella sorokiniana. in Redox Biology in the 21st Century: A New Scientific Discipline, Meeting Abstracts. 2021;:145-145.
doi:10.1016/j.freeradbiomed.2021.08.148 .

Vojvodić, Snežana, Stanić, Marina, Zechmann, Bernd, Dimitrijević, Milena, Opačić, Miloš, Danilović Luković, Jelena, Morina, Arian, Pittman, Jon K., Spasojević, Ivan, "Mechanisms of detoxification of high manganese concentrations by the microalga Chlorella sorokiniana" in Redox Biology in the 21st Century: A New Scientific Discipline, Meeting Abstracts (2021):145-145,
https://doi.org/10.1016/j.freeradbiomed.2021.08.148 . .

TY  - JOUR
AU  - Vojvodić, Snežana
AU  - Stanić, Marina
AU  - Zechmann, Bernd
AU  - Ducic, Tanja
AU  - Žižić, Milan
AU  - Dimitrijević, Milena
AU  - Danilović Luković, Jelena
AU  - Milenković, Milica R.
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2020
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1354
AB  - Microalgae have evolved mechanisms to respond to changes in copper ion availability, which are very important for normal cellular function, to tolerate metal pollution of aquatic ecosystems, and for modulation of copper bioavailability and toxicity to other organisms. Knowledge and application of these mechanisms will benefit the use of microalgae in wastewater processing and biomass production, and the use of copper compounds in the suppression of harmful algal blooms. Here, using electron microscopy, synchrotron radiation-based Fourier transform infrared spectroscopy, electron paramagnetic resonance spectroscopy, and X-ray absorption fine structure spectroscopy, we show that the microalga Chlorella sorokiniana responds promptly to Cu2+ at high non-toxic concentration, by mucilage release, alterations in the architecture of the outer cell wall layer and lipid structures, and polyphosphate accumulation within mucilage matrix. The main route of copper detoxification is by Cu2+ coordination to polyphosphates in penta-coordinated geometry. The sequestrated Cu2+ was accessible and could be released by extracellular chelating agents. Finally, the reduction in Cu2+ to Cu1+ appears also to take place. These findings reveal the biochemical basis of the capacity of microalgae to adapt to high external copper concentrations and to serve as both, sinks and pools of environmental copper.
PB  - Portland Press Ltd, London
T2  - Biochemical Journal
T1  - Mechanisms of detoxification of high copper concentrations by the microalga Chlorella sorokiniana
EP  - 3741
IS  - 19
SP  - 3729
VL  - 477
DO  - 10.1042/BCJ20200600
ER  - 

@article{
author = "Vojvodić, Snežana and Stanić, Marina and Zechmann, Bernd and Ducic, Tanja and Žižić, Milan and Dimitrijević, Milena and Danilović Luković, Jelena and Milenković, Milica R. and Pittman, Jon K. and Spasojević, Ivan",
year = "2020",
abstract = "Microalgae have evolved mechanisms to respond to changes in copper ion availability, which are very important for normal cellular function, to tolerate metal pollution of aquatic ecosystems, and for modulation of copper bioavailability and toxicity to other organisms. Knowledge and application of these mechanisms will benefit the use of microalgae in wastewater processing and biomass production, and the use of copper compounds in the suppression of harmful algal blooms. Here, using electron microscopy, synchrotron radiation-based Fourier transform infrared spectroscopy, electron paramagnetic resonance spectroscopy, and X-ray absorption fine structure spectroscopy, we show that the microalga Chlorella sorokiniana responds promptly to Cu2+ at high non-toxic concentration, by mucilage release, alterations in the architecture of the outer cell wall layer and lipid structures, and polyphosphate accumulation within mucilage matrix. The main route of copper detoxification is by Cu2+ coordination to polyphosphates in penta-coordinated geometry. The sequestrated Cu2+ was accessible and could be released by extracellular chelating agents. Finally, the reduction in Cu2+ to Cu1+ appears also to take place. These findings reveal the biochemical basis of the capacity of microalgae to adapt to high external copper concentrations and to serve as both, sinks and pools of environmental copper.",
publisher = "Portland Press Ltd, London",
journal = "Biochemical Journal",
title = "Mechanisms of detoxification of high copper concentrations by the microalga Chlorella sorokiniana",
pages = "3741-3729",
number = "19",
volume = "477",
doi = "10.1042/BCJ20200600"
}

Vojvodić, S., Stanić, M., Zechmann, B., Ducic, T., Žižić, M., Dimitrijević, M., Danilović Luković, J., Milenković, M. R., Pittman, J. K.,& Spasojević, I.. (2020). Mechanisms of detoxification of high copper concentrations by the microalga Chlorella sorokiniana. in Biochemical Journal
Portland Press Ltd, London., 477(19), 3729-3741.
https://doi.org/10.1042/BCJ20200600

Vojvodić S, Stanić M, Zechmann B, Ducic T, Žižić M, Dimitrijević M, Danilović Luković J, Milenković MR, Pittman JK, Spasojević I. Mechanisms of detoxification of high copper concentrations by the microalga Chlorella sorokiniana. in Biochemical Journal. 2020;477(19):3729-3741.
doi:10.1042/BCJ20200600 .

Vojvodić, Snežana, Stanić, Marina, Zechmann, Bernd, Ducic, Tanja, Žižić, Milan, Dimitrijević, Milena, Danilović Luković, Jelena, Milenković, Milica R., Pittman, Jon K., Spasojević, Ivan, "Mechanisms of detoxification of high copper concentrations by the microalga Chlorella sorokiniana" in Biochemical Journal, 477, no. 19 (2020):3729-3741,
https://doi.org/10.1042/BCJ20200600 . .

TY  - JOUR
AU  - Vojvodić, Snežana
AU  - Danilović Luković, Jelena
AU  - Zechmann, Bernd
AU  - Jevtović, Mima
AU  - Bogdanović Pristov, Jelena
AU  - Stanić, Marina
AU  - Lizzul, Alessandro Marco
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2020
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1371
AB  - The impact of ionizing radiation on microorganisms such as microalgae is a topic of increasing importance for understanding the dynamics of aquatic ecosystems in response to environmental radiation, and for the development of efficient approaches for bioremediation of mining and nuclear power plants wastewaters. Currently, nothing is known about the effects of ionizing radiation on the microalgal cell wall, which represents the first line of defence against chemical and physical environmental stresses. Using various microscopy, spectroscopy and biochemical techniques we show that the unicellular alga Chlorella sorokiniana elicits a fast response to ionizing radiation. Within one day after irradiation with doses of 1-5 Gy, the fibrilar layer of the cell wall became thicker, the fraction of uronic acids was higher, and the capacity to remove the main reactive product of water radiolysis increased. In addition, the isolated cell wall fraction showed significant binding capacity for Cu2+, Mn2+, and Cr3+. The irradiation further increased the binding capacity for Cu2+, which appears to be mainly bound to glucosamine moieties within a chitosan-like polymer in the outer rigid layer of the wall. These results imply that the cell wall represents a dynamic structure that is involved in the protective response of microalgae to ionizing radiation. It appears that microalgae may exhibit a significant control of metal mobility in aquatic ecosystems via biosorption by the cell wall matrix.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Chemosphere
T1  - The effects of ionizing radiation on the structure and antioxidative and metal-binding capacity of the cell wall of microalga Chlorella sorokiniana
VL  - 260
DO  - 10.1016/j.chemosphere.2020.127553
ER  - 

@article{
author = "Vojvodić, Snežana and Danilović Luković, Jelena and Zechmann, Bernd and Jevtović, Mima and Bogdanović Pristov, Jelena and Stanić, Marina and Lizzul, Alessandro Marco and Pittman, Jon K. and Spasojević, Ivan",
year = "2020",
abstract = "The impact of ionizing radiation on microorganisms such as microalgae is a topic of increasing importance for understanding the dynamics of aquatic ecosystems in response to environmental radiation, and for the development of efficient approaches for bioremediation of mining and nuclear power plants wastewaters. Currently, nothing is known about the effects of ionizing radiation on the microalgal cell wall, which represents the first line of defence against chemical and physical environmental stresses. Using various microscopy, spectroscopy and biochemical techniques we show that the unicellular alga Chlorella sorokiniana elicits a fast response to ionizing radiation. Within one day after irradiation with doses of 1-5 Gy, the fibrilar layer of the cell wall became thicker, the fraction of uronic acids was higher, and the capacity to remove the main reactive product of water radiolysis increased. In addition, the isolated cell wall fraction showed significant binding capacity for Cu2+, Mn2+, and Cr3+. The irradiation further increased the binding capacity for Cu2+, which appears to be mainly bound to glucosamine moieties within a chitosan-like polymer in the outer rigid layer of the wall. These results imply that the cell wall represents a dynamic structure that is involved in the protective response of microalgae to ionizing radiation. It appears that microalgae may exhibit a significant control of metal mobility in aquatic ecosystems via biosorption by the cell wall matrix.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Chemosphere",
title = "The effects of ionizing radiation on the structure and antioxidative and metal-binding capacity of the cell wall of microalga Chlorella sorokiniana",
volume = "260",
doi = "10.1016/j.chemosphere.2020.127553"
}

Vojvodić, S., Danilović Luković, J., Zechmann, B., Jevtović, M., Bogdanović Pristov, J., Stanić, M., Lizzul, A. M., Pittman, J. K.,& Spasojević, I.. (2020). The effects of ionizing radiation on the structure and antioxidative and metal-binding capacity of the cell wall of microalga Chlorella sorokiniana. in Chemosphere
Pergamon-Elsevier Science Ltd, Oxford., 260.
https://doi.org/10.1016/j.chemosphere.2020.127553

Vojvodić S, Danilović Luković J, Zechmann B, Jevtović M, Bogdanović Pristov J, Stanić M, Lizzul AM, Pittman JK, Spasojević I. The effects of ionizing radiation on the structure and antioxidative and metal-binding capacity of the cell wall of microalga Chlorella sorokiniana. in Chemosphere. 2020;260.
doi:10.1016/j.chemosphere.2020.127553 .

Vojvodić, Snežana, Danilović Luković, Jelena, Zechmann, Bernd, Jevtović, Mima, Bogdanović Pristov, Jelena, Stanić, Marina, Lizzul, Alessandro Marco, Pittman, Jon K., Spasojević, Ivan, "The effects of ionizing radiation on the structure and antioxidative and metal-binding capacity of the cell wall of microalga Chlorella sorokiniana" in Chemosphere, 260 (2020),
https://doi.org/10.1016/j.chemosphere.2020.127553 . .

TY  - CONF
AU  - Danilović Luković, Jelena
AU  - Zechmann, Bernd
AU  - Vojvodić, Snežana
AU  - Bogdanović Pristov, Jelena
AU  - Stanić, Marina
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2019
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2408
AB  - Cell wall of C. sorokiniana is composed of trilaminar sheath (TLS electron
translucent line inserted between two electron dense lines; the outermost layer is a mature mother
wall, while the thin inner layer is a daughter wall), and fibrilar cell wall. It is noteworthy that the
obtained diameters for untreated microalgae were in accordance with available data. The analysis of TEM micrographs showed that there were no significant changes in the thickness of
TLS for any of the used doses. However, the diameter of fibrillar wall was increased in response
to irradiation for microalgae exposed to 1 Gy and 2 Gy. The thickness of cell wall in microalgae
exposed to 5 Gy was not significantly different than in controls. A similar trend was
observed by gravimetry of dry cell wall isolates normalized to biomass. It is important to note that
no effects of radiation on biomass, at doses applied here, could be observed.
PB  - Institute for Biological Research “Siniša Stanković” and others contributors
C3  - 14th Multinational Congress on Microscopy. September 15–20, 2019, Belgrade, Serbia
T1  - The effects of ionizing radiation on the cell wall of microalgae Chlorella sorokiniana – TEM study
EP  - 153
SP  - 152
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_2408
ER  - 

@conference{
author = "Danilović Luković, Jelena and Zechmann, Bernd and Vojvodić, Snežana and Bogdanović Pristov, Jelena and Stanić, Marina and Pittman, Jon K. and Spasojević, Ivan",
year = "2019",
abstract = "Cell wall of C. sorokiniana is composed of trilaminar sheath (TLS electron
translucent line inserted between two electron dense lines; the outermost layer is a mature mother
wall, while the thin inner layer is a daughter wall), and fibrilar cell wall. It is noteworthy that the
obtained diameters for untreated microalgae were in accordance with available data. The analysis of TEM micrographs showed that there were no significant changes in the thickness of
TLS for any of the used doses. However, the diameter of fibrillar wall was increased in response
to irradiation for microalgae exposed to 1 Gy and 2 Gy. The thickness of cell wall in microalgae
exposed to 5 Gy was not significantly different than in controls. A similar trend was
observed by gravimetry of dry cell wall isolates normalized to biomass. It is important to note that
no effects of radiation on biomass, at doses applied here, could be observed.",
publisher = "Institute for Biological Research “Siniša Stanković” and others contributors",
journal = "14th Multinational Congress on Microscopy. September 15–20, 2019, Belgrade, Serbia",
title = "The effects of ionizing radiation on the cell wall of microalgae Chlorella sorokiniana – TEM study",
pages = "153-152",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_2408"
}

Danilović Luković, J., Zechmann, B., Vojvodić, S., Bogdanović Pristov, J., Stanić, M., Pittman, J. K.,& Spasojević, I.. (2019). The effects of ionizing radiation on the cell wall of microalgae Chlorella sorokiniana – TEM study. in 14th Multinational Congress on Microscopy. September 15–20, 2019, Belgrade, Serbia
Institute for Biological Research “Siniša Stanković” and others contributors., 152-153.
https://hdl.handle.net/21.15107/rcub_rimsi_2408

Danilović Luković J, Zechmann B, Vojvodić S, Bogdanović Pristov J, Stanić M, Pittman JK, Spasojević I. The effects of ionizing radiation on the cell wall of microalgae Chlorella sorokiniana – TEM study. in 14th Multinational Congress on Microscopy. September 15–20, 2019, Belgrade, Serbia. 2019;:152-153.
https://hdl.handle.net/21.15107/rcub_rimsi_2408 .

Danilović Luković, Jelena, Zechmann, Bernd, Vojvodić, Snežana, Bogdanović Pristov, Jelena, Stanić, Marina, Pittman, Jon K., Spasojević, Ivan, "The effects of ionizing radiation on the cell wall of microalgae Chlorella sorokiniana – TEM study" in 14th Multinational Congress on Microscopy. September 15–20, 2019, Belgrade, Serbia (2019):152-153,
https://hdl.handle.net/21.15107/rcub_rimsi_2408 .

TY  - CONF
AU  - Vojvodić, Snežana
AU  - Danilović Luković, Jelena
AU  - Zechmann, Bernd
AU  - Bogdanović Pristov, Jelena
AU  - Stanić, Marina
AU  - Pittman, Jon K.
AU  - Spasojević, Ivan
PY  - 2019
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/2414
AB  - Microalgae are exposed to ionizing radiation from natural (e.g. radionuclides from the soil) and anthropogenic sources (such as radioactive waste, nuclear power accidents, etc). However, the mechanisms of adaptation to radiation are poorly understood. The aim of our study was to determine the effects of X-ray irradiation on the cell wall of Chlorella sorokiniana. C. sorokiniana (CCAP 211/8K) culture was grown in 3N-BBM+V medium, at 22°C with a continuous photon flux of 120 μmol m−2 s−1 for 20 days, reaching stationary phase. Cultures were then exposed to X-rays at doses of 1, 2 and 5 Gy, left under the same conditions for additional 24 h, and analyzed using TEM (postfixation with 1% osmium tetroxide, embedded in resin for soft blocks, and stained with uranyl acetate and lead acetate), and gravimetry. The analysis of TEM micrographs showed that there were no significant changes in the thickness of trilaminar sheath for any of the used doses. However, the diameter of the fibrillar wall was increased in response to irradiation: 105.5 ± 7.5 nm for untreated samples vs. 135.0 ± 9.5 nm (p = 0.015) for microalgae exposed to 1 Gy, and 127.9 ± 7.4 nm (p = 0.036) for exposure to 2 Gy. The thickness of the cell wall in microalgae exposed to 5 Gy (118.6 ± 8.6 nm) was not significantly different than in controls. A similar trend was observed by gravimetry of dry cell wall isolates normalized to biomass. It is important to note that no effects of radiation on biomass, at doses applied here, could be observed. It appears that Chlorella sorokiniana responds promptly to ionizing radiation by fortifying its ‘first line of defense’. The observed changes may be of particular interest for bioremediation, taking into account the capacity of the cell wall to bind water-soluble metals, including radionuclides.
PB  - Taylor & Francis Group
C3  - Journal of Experimental Botany
T1  - Adaptive response of Chlorella sorokiniana to ionizing radiation on the level of cell wall
EP  - 166
IS  - Supp 1
SP  - 166
VL  - 54
DO  - 10.1080/09670262.2019.1626628
ER  - 

@conference{
author = "Vojvodić, Snežana and Danilović Luković, Jelena and Zechmann, Bernd and Bogdanović Pristov, Jelena and Stanić, Marina and Pittman, Jon K. and Spasojević, Ivan",
year = "2019",
abstract = "Microalgae are exposed to ionizing radiation from natural (e.g. radionuclides from the soil) and anthropogenic sources (such as radioactive waste, nuclear power accidents, etc). However, the mechanisms of adaptation to radiation are poorly understood. The aim of our study was to determine the effects of X-ray irradiation on the cell wall of Chlorella sorokiniana. C. sorokiniana (CCAP 211/8K) culture was grown in 3N-BBM+V medium, at 22°C with a continuous photon flux of 120 μmol m−2 s−1 for 20 days, reaching stationary phase. Cultures were then exposed to X-rays at doses of 1, 2 and 5 Gy, left under the same conditions for additional 24 h, and analyzed using TEM (postfixation with 1% osmium tetroxide, embedded in resin for soft blocks, and stained with uranyl acetate and lead acetate), and gravimetry. The analysis of TEM micrographs showed that there were no significant changes in the thickness of trilaminar sheath for any of the used doses. However, the diameter of the fibrillar wall was increased in response to irradiation: 105.5 ± 7.5 nm for untreated samples vs. 135.0 ± 9.5 nm (p = 0.015) for microalgae exposed to 1 Gy, and 127.9 ± 7.4 nm (p = 0.036) for exposure to 2 Gy. The thickness of the cell wall in microalgae exposed to 5 Gy (118.6 ± 8.6 nm) was not significantly different than in controls. A similar trend was observed by gravimetry of dry cell wall isolates normalized to biomass. It is important to note that no effects of radiation on biomass, at doses applied here, could be observed. It appears that Chlorella sorokiniana responds promptly to ionizing radiation by fortifying its ‘first line of defense’. The observed changes may be of particular interest for bioremediation, taking into account the capacity of the cell wall to bind water-soluble metals, including radionuclides.",
publisher = "Taylor & Francis Group",
journal = "Journal of Experimental Botany",
title = "Adaptive response of Chlorella sorokiniana to ionizing radiation on the level of cell wall",
pages = "166-166",
number = "Supp 1",
volume = "54",
doi = "10.1080/09670262.2019.1626628"
}

Vojvodić, S., Danilović Luković, J., Zechmann, B., Bogdanović Pristov, J., Stanić, M., Pittman, J. K.,& Spasojević, I.. (2019). Adaptive response of Chlorella sorokiniana to ionizing radiation on the level of cell wall. in Journal of Experimental Botany
Taylor & Francis Group., 54(Supp 1), 166-166.
https://doi.org/10.1080/09670262.2019.1626628

Vojvodić S, Danilović Luković J, Zechmann B, Bogdanović Pristov J, Stanić M, Pittman JK, Spasojević I. Adaptive response of Chlorella sorokiniana to ionizing radiation on the level of cell wall. in Journal of Experimental Botany. 2019;54(Supp 1):166-166.
doi:10.1080/09670262.2019.1626628 .

Vojvodić, Snežana, Danilović Luković, Jelena, Zechmann, Bernd, Bogdanović Pristov, Jelena, Stanić, Marina, Pittman, Jon K., Spasojević, Ivan, "Adaptive response of Chlorella sorokiniana to ionizing radiation on the level of cell wall" in Journal of Experimental Botany, 54, no. Supp 1 (2019):166-166,
https://doi.org/10.1080/09670262.2019.1626628 . .

TY  - JOUR
AU  - Vidović, Marija
AU  - Morina, Filis
AU  - Milić Komić, Sonja
AU  - Vuleta, A.
AU  - Zechmann, Bernd
AU  - Prokic, Ljiljana
AU  - Veljović-Jovanović, Sonja
PY  - 2016
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/959
AB  - Hydrogen peroxide is an important signalling molecule, involved in regulation of numerous metabolic processes in plants. The most important sources of H2O2 in photosynthetically active cells are chloroplasts and peroxisomes. Here we employed variegated Pelargonium zonale to characterise and compare enzymatic and non-enzymatic components of the antioxidative system in autotrophic and heterotrophic leaf tissues at (sub)cellular level under optimal growth conditions. The results revealed that both leaf tissues had specific strategies to regulate H2O2 levels. In photosynthetic cells, the redox regulatory system was based on ascorbate, and on the activities of thylakoid-bound ascorbate peroxidase (tAPX) and catalase. In this leaf tissue, ascorbate was predominantly localised in the nucleus, peroxisomes, plastids and mitochondria. On the other hand, non-photosynthetic cells contained higher glutathione content, mostly located in mitochondria. The enzymatic antioxidative system in non-photosynthetic cells relied on the ascorbate-glutathione cycle and both Mn and Cu/Zn superoxide dismutase. Interestingly, higher content of ascorbate and glutathione, and higher activities of APX in the cytosol of non-photosynthetic leaf cells compared to the photosynthetic ones, suggest the importance of this compartment in H2O2 regulation. Together, these results imply different regulation of processes linked with H2O2 signalling at subcellular level. Thus, we propose green-white variegated leaves as an excellent system for examination of redox signal transduction and redox communication between two cell types, autotrophic and heterotrophic, within the same organ.
PB  - Wiley, Hoboken
T2  - Plant Biology
T1  - Characterisation of antioxidants in photosynthetic and non-photosynthetic leaf tissues of variegated Pelargonium zonale plants
EP  - 680
IS  - 4
SP  - 669
VL  - 18
DO  - 10.1111/plb.12429
ER  - 

@article{
author = "Vidović, Marija and Morina, Filis and Milić Komić, Sonja and Vuleta, A. and Zechmann, Bernd and Prokic, Ljiljana and Veljović-Jovanović, Sonja",
year = "2016",
abstract = "Hydrogen peroxide is an important signalling molecule, involved in regulation of numerous metabolic processes in plants. The most important sources of H2O2 in photosynthetically active cells are chloroplasts and peroxisomes. Here we employed variegated Pelargonium zonale to characterise and compare enzymatic and non-enzymatic components of the antioxidative system in autotrophic and heterotrophic leaf tissues at (sub)cellular level under optimal growth conditions. The results revealed that both leaf tissues had specific strategies to regulate H2O2 levels. In photosynthetic cells, the redox regulatory system was based on ascorbate, and on the activities of thylakoid-bound ascorbate peroxidase (tAPX) and catalase. In this leaf tissue, ascorbate was predominantly localised in the nucleus, peroxisomes, plastids and mitochondria. On the other hand, non-photosynthetic cells contained higher glutathione content, mostly located in mitochondria. The enzymatic antioxidative system in non-photosynthetic cells relied on the ascorbate-glutathione cycle and both Mn and Cu/Zn superoxide dismutase. Interestingly, higher content of ascorbate and glutathione, and higher activities of APX in the cytosol of non-photosynthetic leaf cells compared to the photosynthetic ones, suggest the importance of this compartment in H2O2 regulation. Together, these results imply different regulation of processes linked with H2O2 signalling at subcellular level. Thus, we propose green-white variegated leaves as an excellent system for examination of redox signal transduction and redox communication between two cell types, autotrophic and heterotrophic, within the same organ.",
publisher = "Wiley, Hoboken",
journal = "Plant Biology",
title = "Characterisation of antioxidants in photosynthetic and non-photosynthetic leaf tissues of variegated Pelargonium zonale plants",
pages = "680-669",
number = "4",
volume = "18",
doi = "10.1111/plb.12429"
}

Vidović, M., Morina, F., Milić Komić, S., Vuleta, A., Zechmann, B., Prokic, L.,& Veljović-Jovanović, S.. (2016). Characterisation of antioxidants in photosynthetic and non-photosynthetic leaf tissues of variegated Pelargonium zonale plants. in Plant Biology
Wiley, Hoboken., 18(4), 669-680.
https://doi.org/10.1111/plb.12429

Vidović M, Morina F, Milić Komić S, Vuleta A, Zechmann B, Prokic L, Veljović-Jovanović S. Characterisation of antioxidants in photosynthetic and non-photosynthetic leaf tissues of variegated Pelargonium zonale plants. in Plant Biology. 2016;18(4):669-680.
doi:10.1111/plb.12429 .

Vidović, Marija, Morina, Filis, Milić Komić, Sonja, Vuleta, A., Zechmann, Bernd, Prokic, Ljiljana, Veljović-Jovanović, Sonja, "Characterisation of antioxidants in photosynthetic and non-photosynthetic leaf tissues of variegated Pelargonium zonale plants" in Plant Biology, 18, no. 4 (2016):669-680,
https://doi.org/10.1111/plb.12429 . .

TY  - JOUR
AU  - Vidović, Marija
AU  - Morina, Filis
AU  - Milić Komić, Sonja
AU  - Zechmann, Bernd
AU  - Albert, Andreas
AU  - Winkler, Jana Barbro
AU  - Veljović-Jovanović, Sonja
PY  - 2015
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/873
AB  - We used variegated Plectranthus coleoides as a model plant with the aim of clarifying whether the effects of realistic ultraviolet-B (UV-B) doses on phenolic metabolism in leaves are mediated by photosynthesis. Plants were exposed to UV-B radiation (0.90Wm(-2)) combined with two photosynthetically active radiation (PAR) intensities [395 and 1350molm(-2)s(-1), low light (LL) and high light (HL)] for 9d in sun simulators. Our study indicates that UV-B component of sunlight stimulates CO2 assimilation and stomatal conductance, depending on background light. UV-B-specific induction of apigenin and cyanidin glycosides was observed in both green and white tissues. However, all the other phenolic subclasses were up to four times more abundant in green leaf tissue. Caffeic and rosmarinic acids, catechin and epicatechin, which are endogenous peroxidase substrates, were depleted at HL in green tissue. This was correlated with increased peroxidase and ascorbate peroxidase activities and increased ascorbate content. The UV-B supplement to HL attenuated antioxidative metabolism and partly recovered the phenolic pool indicating stimulation of the phenylpropanoid pathway. In summary, we propose that ortho-dihydroxy phenolics are involved in antioxidative defence in chlorophyllous tissue upon light excess, while apigenin and cyanidin in white tissue have preferentially UV-screening function.
PB  - Wiley, Hoboken
T2  - Plant Cell and Environment
T1  - Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light
EP  - 979
IS  - 5
SP  - 968
VL  - 38
DO  - 10.1111/pce.12471
ER  - 

@article{
author = "Vidović, Marija and Morina, Filis and Milić Komić, Sonja and Zechmann, Bernd and Albert, Andreas and Winkler, Jana Barbro and Veljović-Jovanović, Sonja",
year = "2015",
abstract = "We used variegated Plectranthus coleoides as a model plant with the aim of clarifying whether the effects of realistic ultraviolet-B (UV-B) doses on phenolic metabolism in leaves are mediated by photosynthesis. Plants were exposed to UV-B radiation (0.90Wm(-2)) combined with two photosynthetically active radiation (PAR) intensities [395 and 1350molm(-2)s(-1), low light (LL) and high light (HL)] for 9d in sun simulators. Our study indicates that UV-B component of sunlight stimulates CO2 assimilation and stomatal conductance, depending on background light. UV-B-specific induction of apigenin and cyanidin glycosides was observed in both green and white tissues. However, all the other phenolic subclasses were up to four times more abundant in green leaf tissue. Caffeic and rosmarinic acids, catechin and epicatechin, which are endogenous peroxidase substrates, were depleted at HL in green tissue. This was correlated with increased peroxidase and ascorbate peroxidase activities and increased ascorbate content. The UV-B supplement to HL attenuated antioxidative metabolism and partly recovered the phenolic pool indicating stimulation of the phenylpropanoid pathway. In summary, we propose that ortho-dihydroxy phenolics are involved in antioxidative defence in chlorophyllous tissue upon light excess, while apigenin and cyanidin in white tissue have preferentially UV-screening function.",
publisher = "Wiley, Hoboken",
journal = "Plant Cell and Environment",
title = "Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light",
pages = "979-968",
number = "5",
volume = "38",
doi = "10.1111/pce.12471"
}

Vidović, M., Morina, F., Milić Komić, S., Zechmann, B., Albert, A., Winkler, J. B.,& Veljović-Jovanović, S.. (2015). Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light. in Plant Cell and Environment
Wiley, Hoboken., 38(5), 968-979.
https://doi.org/10.1111/pce.12471

Vidović M, Morina F, Milić Komić S, Zechmann B, Albert A, Winkler JB, Veljović-Jovanović S. Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light. in Plant Cell and Environment. 2015;38(5):968-979.
doi:10.1111/pce.12471 .

Vidović, Marija, Morina, Filis, Milić Komić, Sonja, Zechmann, Bernd, Albert, Andreas, Winkler, Jana Barbro, Veljović-Jovanović, Sonja, "Ultraviolet-B component of sunlight stimulates photosynthesis and flavonoid accumulation in variegated Plectranthus coleoides leaves depending on background light" in Plant Cell and Environment, 38, no. 5 (2015):968-979,
https://doi.org/10.1111/pce.12471 . .

TY  - JOUR
AU  - Vidović, Marija
AU  - Morina, Filis
AU  - Milić Komić, Sonja
AU  - Albert, Andreas
AU  - Zechmann, Bernd
AU  - Tosti, Tomislav
AU  - Winkler, Jana Barbro
AU  - Veljović-Jovanović, Sonja
PY  - 2015
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/858
AB  - We studied the specific effects of high photosynthetically active radiation (PAR, 400-700 nm) and ecologically relevant UV-B radiation (0.90 W m(-2)) on antioxidative and phenolic metabolism by exploiting the green-white leaf variegation of Pelargonium zonale plants. This is a suitable model system for examining "source-sink" interactions within the same leaf. High PAR intensity (1350 mu mol m(-2) s(-1)) and UV-B radiation induced different responses in green and white leaf sectors. High PAR intensity had a greater influence on green tissue, triggering the accumulation of phenylpropanoids and flavonoids with strong antioxidative function. Induced phenolics, together with ascorbate, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) provided efficient defense against potential oxidative pressure. UV-B-induced up-regulation of non-phenolic H2O2 scavengers in green leaf sectors was greater than high PAR-induced changes, indicating a UV-B role in antioxidative defense under light excess; on the contrary, minimal effects were observed in white tissue. However, UV-B radiation had greater influence on phenolics in white leaf sections compared to green ones, inducing accumulation of phenolic glycosides whose function was UV-B screening rather than antioxidative. By stimulation of starch and sucrose breakdown and carbon allocation in the form of soluble sugars from "source" (green) tissue to "sink" (white) tissue, UV-B radiation compensated the absence of photosynthetic activity and phenylpropanoid and flavonoid biosynthesis in white sectors.
PB  - Elsevier France-Editions Scientifiques Medicales Elsevier, Issy-Les-Moulineaux
T2  - Plant Physiology and Biochemistry
T1  - Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity
EP  - 55
SP  - 44
VL  - 93
DO  - 10.1016/j.plaphy.2015.01.008
ER  - 

@article{
author = "Vidović, Marija and Morina, Filis and Milić Komić, Sonja and Albert, Andreas and Zechmann, Bernd and Tosti, Tomislav and Winkler, Jana Barbro and Veljović-Jovanović, Sonja",
year = "2015",
abstract = "We studied the specific effects of high photosynthetically active radiation (PAR, 400-700 nm) and ecologically relevant UV-B radiation (0.90 W m(-2)) on antioxidative and phenolic metabolism by exploiting the green-white leaf variegation of Pelargonium zonale plants. This is a suitable model system for examining "source-sink" interactions within the same leaf. High PAR intensity (1350 mu mol m(-2) s(-1)) and UV-B radiation induced different responses in green and white leaf sectors. High PAR intensity had a greater influence on green tissue, triggering the accumulation of phenylpropanoids and flavonoids with strong antioxidative function. Induced phenolics, together with ascorbate, ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (CAT, EC 1.11.1.6) provided efficient defense against potential oxidative pressure. UV-B-induced up-regulation of non-phenolic H2O2 scavengers in green leaf sectors was greater than high PAR-induced changes, indicating a UV-B role in antioxidative defense under light excess; on the contrary, minimal effects were observed in white tissue. However, UV-B radiation had greater influence on phenolics in white leaf sections compared to green ones, inducing accumulation of phenolic glycosides whose function was UV-B screening rather than antioxidative. By stimulation of starch and sucrose breakdown and carbon allocation in the form of soluble sugars from "source" (green) tissue to "sink" (white) tissue, UV-B radiation compensated the absence of photosynthetic activity and phenylpropanoid and flavonoid biosynthesis in white sectors.",
publisher = "Elsevier France-Editions Scientifiques Medicales Elsevier, Issy-Les-Moulineaux",
journal = "Plant Physiology and Biochemistry",
title = "Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity",
pages = "55-44",
volume = "93",
doi = "10.1016/j.plaphy.2015.01.008"
}

Vidović, M., Morina, F., Milić Komić, S., Albert, A., Zechmann, B., Tosti, T., Winkler, J. B.,& Veljović-Jovanović, S.. (2015). Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity. in Plant Physiology and Biochemistry
Elsevier France-Editions Scientifiques Medicales Elsevier, Issy-Les-Moulineaux., 93, 44-55.
https://doi.org/10.1016/j.plaphy.2015.01.008

Vidović M, Morina F, Milić Komić S, Albert A, Zechmann B, Tosti T, Winkler JB, Veljović-Jovanović S. Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity. in Plant Physiology and Biochemistry. 2015;93:44-55.
doi:10.1016/j.plaphy.2015.01.008 .

Vidović, Marija, Morina, Filis, Milić Komić, Sonja, Albert, Andreas, Zechmann, Bernd, Tosti, Tomislav, Winkler, Jana Barbro, Veljović-Jovanović, Sonja, "Carbon allocation from source to sink leaf tissue in relation to flavonoid biosynthesis in variegated Pelargonium zonale under UV-B radiation and high PAR intensity" in Plant Physiology and Biochemistry, 93 (2015):44-55,
https://doi.org/10.1016/j.plaphy.2015.01.008 . .

TY  - JOUR
AU  - Tolin, Serena
AU  - Arrigoni, Giorgio
AU  - Trentin, Anna Rita
AU  - Veljović-Jovanović, Sonja
AU  - Pivato, Micaela
AU  - Zechmann, Bernd
AU  - Masi, Antonio
PY  - 2013
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/679
AB  - The existence of a gamma-glutamyl cycle consisting of intracellular GSH synthesis, extrusion to the apoplastic space and recovery by gamma-glutamyl transferase (GGT)-assisted degradation into its constituent amino acids, has been demonstrated in plants. To address the significance of this cycle in plant cells, we performed integrated biochemical, immunocytochemical, and quantitative proteomics analyses in the Arabidopsis thaliana ggt1 knockout mutant (lacking apoplastic GGT1 isoform) and its corresponding wild-type (WT). The ggt1 knockout leaves exhibited an increased ascorbate and GSH content, increased apoplastic GSH content, and enhanced protein carbonylations in the low-molecular weight range compared to WT. The combined iTRAQ and LC-MS/MS-based quantitative proteomics approach identified 70 proteins (out of 1013 identified proteins) whose abundance was significantly different in leaves of ggt1 mutant compared to WT, with a fold change 1.5. Mining of the proteome data for GSH-associated genes showed that disruption of gamma-glutamyl cycle in ggt1 knockout-leaves was associated with the induction of genes encoding four GSTs in the phi class (GSTF2, GSTF6, GSTF9, and GSTF10), a GSH peroxidase (GPX1), and glyoxylase II. Proteins with a lower abundance compared to the WT are involved in chloroplast functions, carbohydrate/maltose metabolism, and vegetative storage protein synthesis. Present findings suggest that GGT1 plays a role in redox signaling. The disruption of the gamma-glutamyl cycle in the ggt1 mutant results in pleiotropic effects related to biotic and abiotic stress response, antioxidant metabolism, senescence, carbohydrate metabolism, and photosynthesis, with strong implications for plant adaptation to the environment.
PB  - Wiley, Hoboken
T2  - Proteomics
T1  - Biochemical and quantitative proteomics investigations in Arabidopsis ggt1 mutant leaves reveal a role for the gamma-glutamyl cycle in plant's adaptation to environment
EP  - 2045
IS  - 12-13
SP  - 2031
VL  - 13
DO  - 10.1002/pmic.201200479
ER  - 

@article{
author = "Tolin, Serena and Arrigoni, Giorgio and Trentin, Anna Rita and Veljović-Jovanović, Sonja and Pivato, Micaela and Zechmann, Bernd and Masi, Antonio",
year = "2013",
abstract = "The existence of a gamma-glutamyl cycle consisting of intracellular GSH synthesis, extrusion to the apoplastic space and recovery by gamma-glutamyl transferase (GGT)-assisted degradation into its constituent amino acids, has been demonstrated in plants. To address the significance of this cycle in plant cells, we performed integrated biochemical, immunocytochemical, and quantitative proteomics analyses in the Arabidopsis thaliana ggt1 knockout mutant (lacking apoplastic GGT1 isoform) and its corresponding wild-type (WT). The ggt1 knockout leaves exhibited an increased ascorbate and GSH content, increased apoplastic GSH content, and enhanced protein carbonylations in the low-molecular weight range compared to WT. The combined iTRAQ and LC-MS/MS-based quantitative proteomics approach identified 70 proteins (out of 1013 identified proteins) whose abundance was significantly different in leaves of ggt1 mutant compared to WT, with a fold change 1.5. Mining of the proteome data for GSH-associated genes showed that disruption of gamma-glutamyl cycle in ggt1 knockout-leaves was associated with the induction of genes encoding four GSTs in the phi class (GSTF2, GSTF6, GSTF9, and GSTF10), a GSH peroxidase (GPX1), and glyoxylase II. Proteins with a lower abundance compared to the WT are involved in chloroplast functions, carbohydrate/maltose metabolism, and vegetative storage protein synthesis. Present findings suggest that GGT1 plays a role in redox signaling. The disruption of the gamma-glutamyl cycle in the ggt1 mutant results in pleiotropic effects related to biotic and abiotic stress response, antioxidant metabolism, senescence, carbohydrate metabolism, and photosynthesis, with strong implications for plant adaptation to the environment.",
publisher = "Wiley, Hoboken",
journal = "Proteomics",
title = "Biochemical and quantitative proteomics investigations in Arabidopsis ggt1 mutant leaves reveal a role for the gamma-glutamyl cycle in plant's adaptation to environment",
pages = "2045-2031",
number = "12-13",
volume = "13",
doi = "10.1002/pmic.201200479"
}

Tolin, S., Arrigoni, G., Trentin, A. R., Veljović-Jovanović, S., Pivato, M., Zechmann, B.,& Masi, A.. (2013). Biochemical and quantitative proteomics investigations in Arabidopsis ggt1 mutant leaves reveal a role for the gamma-glutamyl cycle in plant's adaptation to environment. in Proteomics
Wiley, Hoboken., 13(12-13), 2031-2045.
https://doi.org/10.1002/pmic.201200479

Tolin S, Arrigoni G, Trentin AR, Veljović-Jovanović S, Pivato M, Zechmann B, Masi A. Biochemical and quantitative proteomics investigations in Arabidopsis ggt1 mutant leaves reveal a role for the gamma-glutamyl cycle in plant's adaptation to environment. in Proteomics. 2013;13(12-13):2031-2045.
doi:10.1002/pmic.201200479 .

Tolin, Serena, Arrigoni, Giorgio, Trentin, Anna Rita, Veljović-Jovanović, Sonja, Pivato, Micaela, Zechmann, Bernd, Masi, Antonio, "Biochemical and quantitative proteomics investigations in Arabidopsis ggt1 mutant leaves reveal a role for the gamma-glutamyl cycle in plant's adaptation to environment" in Proteomics, 13, no. 12-13 (2013):2031-2045,
https://doi.org/10.1002/pmic.201200479 . .