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Scott A Steinert - One of the best experts on this subject based on the ideXlab platform.
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single cell gel comet assay applied to the analysis of uv radiation induced dna damage in Rhodomonas sp cryptophyta
Photochemistry and Photobiology, 2001Co-Authors: Miguel P Sastre, Maria Vernet, Scott A SteinertAbstract:The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at sites of pyrimidine dimers. The main objective of this work is to evaluate the comet assay to detect UV-induced damage in DNA after an initial treatment of cells with T4 endonuclease V. This work was conducted on Rhodomonas sp. (Cryptophyta), a marine unicellular flagellate. Cells of Rhodomonas sp. were exposed to 12 h visible + ultraviolet-A + ultraviolet-B (VIS + UVA + UVB) and VIS (control), with and without T4 endonuclease V. Cells exposed to VIS + UVA + UVB showed approximately 200% more damage than control if these were treated with T4 endonuclease V. Rhodomonas sp. were exposed to 3, 6, 9 and 12 h of VIS, VIS + UVA and VIS + UVA + UVB. Damage induced by VIS + UVA + UVB as detected by the comet assay increased along with exposure time. However, damage caused by VIS and VIS + UVA remained relatively constant at all times. Results of this study indicate that the comet assay is more sensitive to UV radiation damage when used in conjunction with T4 endonuclease V. This modification of the comet assay can be used as an alternative technique to detect DNA damage in single cells caused by UV radiation.
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Single-cell gel/comet assay applied to the analysis of UV radiation-induced DNA damage in Rhodomonas sp. (Cryptophyta).
Photochemistry and Photobiology, 2001Co-Authors: Miguel P Sastre, Maria Vernet, Scott A SteinertAbstract:The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at sites of pyrimidine dimers. The main objective of this work is to evaluate the comet assay to detect UV-induced damage in DNA after an initial treatment of cells with T4 endonuclease V. This work was conducted on Rhodomonas sp. (Cryptophyta), a marine unicellular flagellate. Cells of Rhodomonas sp. were exposed to 12 h visible + ultraviolet-A + ultraviolet-B (VIS + UVA + UVB) and VIS (control), with and without T4 endonuclease V. Cells exposed to VIS + UVA + UVB showed approximately 200% more damage than control if these were treated with T4 endonuclease V. Rhodomonas sp. were exposed to 3, 6, 9 and 12 h of VIS, VIS + UVA and VIS + UVA + UVB. Damage induced by VIS + UVA + UVB as detected by the comet assay increased along with exposure time. However, damage caused by VIS and VIS + UVA remained relatively constant at all times. Results of this study indicate that the comet assay is more sensitive to UV radiation damage when used in conjunction with T4 endonuclease V. This modification of the comet assay can be used as an alternative technique to detect DNA damage in single cells caused by UV radiation.
P C Oostlander - One of the best experts on this subject based on the ideXlab platform.
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growth and fatty acid content of Rhodomonas sp under day night cycles of light and temperature
Algal Research-Biomass Biofuels and Bioproducts, 2020Co-Authors: P C Oostlander, J Van Houcke, Rene H Wijffels, Maria J BarbosaAbstract:Abstract The biomass composition, namely the fatty composition, of microalgae used in aqua feed is of great importance for the nutritional value of the biomass. Day:night cycles of light and temperature could influence the growth and biomass composition of microalgae. To study the effect of these cycles on Rhodomonas sp. the algae were grown under 16:8 day:night cycles in lab-scale photobioreactors running as turbidostat. Different temperature and light intensities were applied during the light phase. Synchronized cell cycles were observed for Rhodomonas sp. under day:night conditions with oscillating cell size, cell number, biomass concentration and fatty acid content and composition. Cells increased in size during the light phase, storing energy, with cell division scheduled in the dark phase. The introduction of a 16:8 day:night cycle did not affect the biomass yield on light, when operating at optimal conditions of light (150 μmol m−2 s−1) and temperature (21 °C). However, under high light (600 μmol m−2 s−1) or temperature (25 °C), an increased biomass yield on light of up to 22% was found under day:night cycles in comparison to continuous conditions under equal light and temperature levels. Implementation of a day:night cycle increased the maximum daytime temperature for Rhodomonas sp. from 25 °C to 30 °C. The fatty acid content and composition was influence by the implementation of day:night cycles. Daily fluctuations in total fatty acid content from 76 ± 2 mg gDW−1 at the end of the light phase to 94 ± 2 mg gDW−1 in the first hours of the light phase are found. The eicosapentaenoic acid and docosahexaenoic acid content fluctuated by 30% (12.1–16.1 mgEPA+DHA gDW−1) on a daily basis. These daily fluctuations can be exploited in aqua feed applications by selecting a specific time of the day to harvest algae.
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production of Rhodomonas sp at pilot scale under sunlight conditions
Algal Research-Biomass Biofuels and Bioproducts, 2020Co-Authors: P C Oostlander, C Latsos, J Van Houcke, Rene H Wijffels, Maria J BarbosaAbstract:Abstract Rhodomonas sp., is an important microalga for aquaculture feed applications and gained increased research interest over the past few years. While efforts to optimise cultivation of the strain have been studied in detail under laboratory conditions, Rhodomonas sp. has never been grown in photobioreactors at large scale under outdoor light conditions. To study the industrial potential of this strain, we cultivated Rhodomonas sp. in three identical tubular photobioreactors with 200 l working volume each, located in a greenhouse using sunlight conditions only. Growth experiments were performed from February with winter light conditions ( 50 mol m−2 d−1) in July, representing all sunlight conditions in the Netherlands. All nutrients were supplied in surplus and temperature and pH were maintained at optimum values for growth of Rhodomonas sp., based on lab data. The total light per reactor was calculated using a ray-tracing analysis to allow calculations based on the light reaching each individual reactor. Rhodomonas sp. grew under all tested light conditions. Biomass yield on light decreased with increasing light conditions from 0.43 ± 0.21 g mol−1 to 0.18 ± 0.04 g mol−1 at 0–10 molph m−2 d−1 to 30–40 molph m−2 d−1. Biomass productivities increased with increasing light from 0.09 ± 0.04 g l−1 d−1 to 0.19 ± 0.06 g l−1 d−1, for 0–10 and 30–40 molph m−2 d−1. We obtained a 2–5 fold increase in biomass productivity compared to previous reports on Rhodomonas sp. cultivation using artificial light at large scale. Our results show that Rhodomonas sp. can be grown at pilot scale using sunlight conditions and further improvements can be reached in the future.
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optimization of Rhodomonas sp under continuous cultivation for industrial applications in aquaculture
Algal Research-Biomass Biofuels and Bioproducts, 2020Co-Authors: P C Oostlander, J Van Houcke, Rene H Wijffels, Maria J BarbosaAbstract:Abstract The microalgae species Rhodomonas sp. is commonly used in aquaculture for its high nutritional value due to the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content. Understanding the effect of cultivation parameters on biomass production rate and composition is presently limited, however essential in further commercialization of this strain. Under nutrient replete conditions, light intensity and temperature are the main factors determining biomass growth and composition. Therefore, the combined effect of light and temperature on the biomass production rate and biomass composition of Rhodomonas sp. was studied using a statistical Design of Experiment approach. Rhodomonas sp. was cultivated under continuous (turbidostat) conditions in lab-scale reactor systems (1.8 l) under different temperature (15–20–25–30 °C) and light conditions (60–195–330–465–600 μmol m−2 s−1). Stable biomass production was observed under all conditions except experiments performed at 30 °C, which led to cell death. Under optimized growth conditions, high growth rates (>1.0d−1) and high biomass production rates, up to 1.5 g l−1 d−1, were obtained in this study. The biomass production rate reported here is >10-fold higher than values reported in literature on Rhodomonas sp. The optimal temperature for maximal growth was found at T = 22–24 °C under all light conditions. The maximum biomass yield on light (Yx,ph – 0.87 g mol−1) was found at light levels between 110 and 220 μmol m−2 s−1. The fatty acid profile was only significantly influenced by temperature, with higher EPA and DHA contents at lower temperatures (15 °C). A total fatty acid (TFA) content of 8–10% of the total dry-weight was found for all tested conditions. The EPA content fluctuated between 9 and 16% of TFA and DHA content between 6 and 9% of TFA, only affected by temperature. A maximum EPA + DHA production rate of 114 mg l‐−1 d−1 was obtained at 20 °C and high light (600 μmol m−2 s−1) conditions.
Maria Vernet - One of the best experts on this subject based on the ideXlab platform.
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Single-cell gel/comet assay applied to the analysis of UV radiation-induced DNA damage in Rhodomonas sp. (Cryptophyta).
Photochemistry and Photobiology, 2001Co-Authors: Miguel P Sastre, Maria Vernet, Scott A SteinertAbstract:The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at sites of pyrimidine dimers. The main objective of this work is to evaluate the comet assay to detect UV-induced damage in DNA after an initial treatment of cells with T4 endonuclease V. This work was conducted on Rhodomonas sp. (Cryptophyta), a marine unicellular flagellate. Cells of Rhodomonas sp. were exposed to 12 h visible + ultraviolet-A + ultraviolet-B (VIS + UVA + UVB) and VIS (control), with and without T4 endonuclease V. Cells exposed to VIS + UVA + UVB showed approximately 200% more damage than control if these were treated with T4 endonuclease V. Rhodomonas sp. were exposed to 3, 6, 9 and 12 h of VIS, VIS + UVA and VIS + UVA + UVB. Damage induced by VIS + UVA + UVB as detected by the comet assay increased along with exposure time. However, damage caused by VIS and VIS + UVA remained relatively constant at all times. Results of this study indicate that the comet assay is more sensitive to UV radiation damage when used in conjunction with T4 endonuclease V. This modification of the comet assay can be used as an alternative technique to detect DNA damage in single cells caused by UV radiation.
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single cell gel comet assay applied to the analysis of uv radiation induced dna damage in Rhodomonas sp cryptophyta
Photochemistry and Photobiology, 2001Co-Authors: Miguel P Sastre, Maria Vernet, Scott A SteinertAbstract:The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at sites of pyrimidine dimers. The main objective of this work is to evaluate the comet assay to detect UV-induced damage in DNA after an initial treatment of cells with T4 endonuclease V. This work was conducted on Rhodomonas sp. (Cryptophyta), a marine unicellular flagellate. Cells of Rhodomonas sp. were exposed to 12 h visible + ultraviolet-A + ultraviolet-B (VIS + UVA + UVB) and VIS (control), with and without T4 endonuclease V. Cells exposed to VIS + UVA + UVB showed approximately 200% more damage than control if these were treated with T4 endonuclease V. Rhodomonas sp. were exposed to 3, 6, 9 and 12 h of VIS, VIS + UVA and VIS + UVA + UVB. Damage induced by VIS + UVA + UVB as detected by the comet assay increased along with exposure time. However, damage caused by VIS and VIS + UVA remained relatively constant at all times. Results of this study indicate that the comet assay is more sensitive to UV radiation damage when used in conjunction with T4 endonuclease V. This modification of the comet assay can be used as an alternative technique to detect DNA damage in single cells caused by UV radiation.
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the phycobilin signatures of chloroplasts from three dinoflagellate species a microanalytical study of dinophysis caudata d fortii and d acuminata dinophysiales dinophyceae
Journal of Phycology, 1998Co-Authors: Christopher D Hewes, Greg B Mitchell, Tiffany Moisan, Maria Vernet, Freda M H ReidAbstract:The absorbance and fluorescence emission spectra for three species of Dinophysis, D. caudata Saville-Kent, D. fortii Pavillard, and D. acuminata Claparede et Lach- mann, were obtained through an in vivo microanalytical technique using a new type of transparent filter. The pig- ment signatures of these Dinophysis species were compared to those of Synechococcus Nageli, a cryptophyte, and two wild rhodophytes, as well as those of another dinoflagellate, a diatom, and a chlorophyte. Phycobilins are not consid- ered a native protein group for dinoflagellates, yet the ab- sorption and fluorescence properties of the three Dino- physis species were demonstrated to closely resemble phy- cobilins and chlorophylls of Rhodomonas Karsten (Cryp- tophyceae). Analyses of Dinophysis species using epifluorescence microscopy found no additional nucleus or nuclear remnant as would be contributed by an endosym- biont.
Miguel P Sastre - One of the best experts on this subject based on the ideXlab platform.
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single cell gel comet assay applied to the analysis of uv radiation induced dna damage in Rhodomonas sp cryptophyta
Photochemistry and Photobiology, 2001Co-Authors: Miguel P Sastre, Maria Vernet, Scott A SteinertAbstract:The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at sites of pyrimidine dimers. The main objective of this work is to evaluate the comet assay to detect UV-induced damage in DNA after an initial treatment of cells with T4 endonuclease V. This work was conducted on Rhodomonas sp. (Cryptophyta), a marine unicellular flagellate. Cells of Rhodomonas sp. were exposed to 12 h visible + ultraviolet-A + ultraviolet-B (VIS + UVA + UVB) and VIS (control), with and without T4 endonuclease V. Cells exposed to VIS + UVA + UVB showed approximately 200% more damage than control if these were treated with T4 endonuclease V. Rhodomonas sp. were exposed to 3, 6, 9 and 12 h of VIS, VIS + UVA and VIS + UVA + UVB. Damage induced by VIS + UVA + UVB as detected by the comet assay increased along with exposure time. However, damage caused by VIS and VIS + UVA remained relatively constant at all times. Results of this study indicate that the comet assay is more sensitive to UV radiation damage when used in conjunction with T4 endonuclease V. This modification of the comet assay can be used as an alternative technique to detect DNA damage in single cells caused by UV radiation.
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Single-cell gel/comet assay applied to the analysis of UV radiation-induced DNA damage in Rhodomonas sp. (Cryptophyta).
Photochemistry and Photobiology, 2001Co-Authors: Miguel P Sastre, Maria Vernet, Scott A SteinertAbstract:The single-cell gel/comet assay is an electrophoretic technique used to detect single-strand breaks in DNA. Damage is assessed examining individual cells under an epifluorescent microscope. UV-induced DNA damage consists mostly of the formation of pyrimidine dimers; therefore, most of the damage cannot be detected using a standard comet assay. The enzyme T4 endonuclease V breaks DNA strands at sites of pyrimidine dimers. The main objective of this work is to evaluate the comet assay to detect UV-induced damage in DNA after an initial treatment of cells with T4 endonuclease V. This work was conducted on Rhodomonas sp. (Cryptophyta), a marine unicellular flagellate. Cells of Rhodomonas sp. were exposed to 12 h visible + ultraviolet-A + ultraviolet-B (VIS + UVA + UVB) and VIS (control), with and without T4 endonuclease V. Cells exposed to VIS + UVA + UVB showed approximately 200% more damage than control if these were treated with T4 endonuclease V. Rhodomonas sp. were exposed to 3, 6, 9 and 12 h of VIS, VIS + UVA and VIS + UVA + UVB. Damage induced by VIS + UVA + UVB as detected by the comet assay increased along with exposure time. However, damage caused by VIS and VIS + UVA remained relatively constant at all times. Results of this study indicate that the comet assay is more sensitive to UV radiation damage when used in conjunction with T4 endonuclease V. This modification of the comet assay can be used as an alternative technique to detect DNA damage in single cells caused by UV radiation.
Maria J Barbosa - One of the best experts on this subject based on the ideXlab platform.
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growth and fatty acid content of Rhodomonas sp under day night cycles of light and temperature
Algal Research-Biomass Biofuels and Bioproducts, 2020Co-Authors: P C Oostlander, J Van Houcke, Rene H Wijffels, Maria J BarbosaAbstract:Abstract The biomass composition, namely the fatty composition, of microalgae used in aqua feed is of great importance for the nutritional value of the biomass. Day:night cycles of light and temperature could influence the growth and biomass composition of microalgae. To study the effect of these cycles on Rhodomonas sp. the algae were grown under 16:8 day:night cycles in lab-scale photobioreactors running as turbidostat. Different temperature and light intensities were applied during the light phase. Synchronized cell cycles were observed for Rhodomonas sp. under day:night conditions with oscillating cell size, cell number, biomass concentration and fatty acid content and composition. Cells increased in size during the light phase, storing energy, with cell division scheduled in the dark phase. The introduction of a 16:8 day:night cycle did not affect the biomass yield on light, when operating at optimal conditions of light (150 μmol m−2 s−1) and temperature (21 °C). However, under high light (600 μmol m−2 s−1) or temperature (25 °C), an increased biomass yield on light of up to 22% was found under day:night cycles in comparison to continuous conditions under equal light and temperature levels. Implementation of a day:night cycle increased the maximum daytime temperature for Rhodomonas sp. from 25 °C to 30 °C. The fatty acid content and composition was influence by the implementation of day:night cycles. Daily fluctuations in total fatty acid content from 76 ± 2 mg gDW−1 at the end of the light phase to 94 ± 2 mg gDW−1 in the first hours of the light phase are found. The eicosapentaenoic acid and docosahexaenoic acid content fluctuated by 30% (12.1–16.1 mgEPA+DHA gDW−1) on a daily basis. These daily fluctuations can be exploited in aqua feed applications by selecting a specific time of the day to harvest algae.
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production of Rhodomonas sp at pilot scale under sunlight conditions
Algal Research-Biomass Biofuels and Bioproducts, 2020Co-Authors: P C Oostlander, C Latsos, J Van Houcke, Rene H Wijffels, Maria J BarbosaAbstract:Abstract Rhodomonas sp., is an important microalga for aquaculture feed applications and gained increased research interest over the past few years. While efforts to optimise cultivation of the strain have been studied in detail under laboratory conditions, Rhodomonas sp. has never been grown in photobioreactors at large scale under outdoor light conditions. To study the industrial potential of this strain, we cultivated Rhodomonas sp. in three identical tubular photobioreactors with 200 l working volume each, located in a greenhouse using sunlight conditions only. Growth experiments were performed from February with winter light conditions ( 50 mol m−2 d−1) in July, representing all sunlight conditions in the Netherlands. All nutrients were supplied in surplus and temperature and pH were maintained at optimum values for growth of Rhodomonas sp., based on lab data. The total light per reactor was calculated using a ray-tracing analysis to allow calculations based on the light reaching each individual reactor. Rhodomonas sp. grew under all tested light conditions. Biomass yield on light decreased with increasing light conditions from 0.43 ± 0.21 g mol−1 to 0.18 ± 0.04 g mol−1 at 0–10 molph m−2 d−1 to 30–40 molph m−2 d−1. Biomass productivities increased with increasing light from 0.09 ± 0.04 g l−1 d−1 to 0.19 ± 0.06 g l−1 d−1, for 0–10 and 30–40 molph m−2 d−1. We obtained a 2–5 fold increase in biomass productivity compared to previous reports on Rhodomonas sp. cultivation using artificial light at large scale. Our results show that Rhodomonas sp. can be grown at pilot scale using sunlight conditions and further improvements can be reached in the future.
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optimization of Rhodomonas sp under continuous cultivation for industrial applications in aquaculture
Algal Research-Biomass Biofuels and Bioproducts, 2020Co-Authors: P C Oostlander, J Van Houcke, Rene H Wijffels, Maria J BarbosaAbstract:Abstract The microalgae species Rhodomonas sp. is commonly used in aquaculture for its high nutritional value due to the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content. Understanding the effect of cultivation parameters on biomass production rate and composition is presently limited, however essential in further commercialization of this strain. Under nutrient replete conditions, light intensity and temperature are the main factors determining biomass growth and composition. Therefore, the combined effect of light and temperature on the biomass production rate and biomass composition of Rhodomonas sp. was studied using a statistical Design of Experiment approach. Rhodomonas sp. was cultivated under continuous (turbidostat) conditions in lab-scale reactor systems (1.8 l) under different temperature (15–20–25–30 °C) and light conditions (60–195–330–465–600 μmol m−2 s−1). Stable biomass production was observed under all conditions except experiments performed at 30 °C, which led to cell death. Under optimized growth conditions, high growth rates (>1.0d−1) and high biomass production rates, up to 1.5 g l−1 d−1, were obtained in this study. The biomass production rate reported here is >10-fold higher than values reported in literature on Rhodomonas sp. The optimal temperature for maximal growth was found at T = 22–24 °C under all light conditions. The maximum biomass yield on light (Yx,ph – 0.87 g mol−1) was found at light levels between 110 and 220 μmol m−2 s−1. The fatty acid profile was only significantly influenced by temperature, with higher EPA and DHA contents at lower temperatures (15 °C). A total fatty acid (TFA) content of 8–10% of the total dry-weight was found for all tested conditions. The EPA content fluctuated between 9 and 16% of TFA and DHA content between 6 and 9% of TFA, only affected by temperature. A maximum EPA + DHA production rate of 114 mg l‐−1 d−1 was obtained at 20 °C and high light (600 μmol m−2 s−1) conditions.
