scholarly journals The photosynthetic activity of Paramecium bursaria endosymbiotic algae in varying temperature conditions

2017 ◽  
Author(s):  
Katarzyna Możdżeń ◽  
Patrycja Zagata-Leśnicka ◽  
Mateusz Ślęczka ◽  
Magdalena Greczek-Stachura
Keyword(s):  
Fluorescence Spectra ◽  
Photosynthetic Activity ◽  
Red Light ◽  
Paramecium Bursaria ◽  
Green Fluorescence ◽  
Chlorella Sp ◽  
Fluorescence Measurements ◽  
Higher Temperature ◽  
Endosymbiotic Algae ◽  
C 30

The aim of this study was to investigate the effect of higher temperatures on the photosynthesis of endosymbiotic Chlorella sp. of two Paramecium bursaria Ehrenberg 1831 strains originating from regions with a warmer and colder climate (Ardmore – USA and Kamchatka – Russia, respectively). After seven days of protozoa incubation at 18°C (control), 21°C, 24°C, 27°C, 30°C and 33°C, the chlorophyll a fluorescence measurements were carried out and fluorescence spectra were measured in blue-green and red light. As a result of the studies, a significant effect of higher temperature on the photosynthesis process of P. bursaria endosymbionts was observed. Weekly incubation at 33°C was lethal for both protozoan strains in comparison to the control temperature (18°C). The blue-green fluorescence spectra were characterised by marked peaks at 450 nm and 490 nm. Within the red light range, the peak was observed at about 690 nm with a lesser arm at 730 nm. Endosymbionts from Kamchatka were more sensitive to the temperature increase than algae from areas with relatively warm climates.

Photosynthetic efficiency of endosymbiotic algae of Paramecium bursaria originating from locations with cold and warm climates

2018 ◽  
Vol 47 (2) ◽  
pp. 202-210
Author(s):  
Katarzyna Możdżeń ◽  
Patrycja Z. Leśnicka ◽  
Tomasz Burnecki ◽  
Sylwia Śliwińska-Wilczewska ◽  
Andrzej Skoczowski ◽  
...  
Keyword(s):  
Photosynthetic Activity ◽  
Cold Climate ◽  
Paramecium Bursaria ◽  
Control Group ◽  
Constant Darkness ◽  
Light Conditions ◽  
Warm Climate ◽  
Symbiotic Algae ◽  
Different Temperatures ◽  
Endosymbiotic Algae

Abstract Paramecium bursaria (Ciliophora) is a cosmopolitan unicellular organism that plays a significant role in aquatic ecosystems. P. bursaria contains symbiotic algae and this association is a mutual symbiosis. The aim of the present study was to determine the activity of photosystem II (PSII) in Chlorella sp. inside P. bursaria cells. Ciliates were incubated for 7 days at different temperatures from 6 to 18°C, under the circadian cycle: 12 h light/12 h dark, at light intensity of 200 μmol m-2 s-1 and under constant darkness conditions. The control group was kept at a temperature of 18°C under constant light conditions. Changes in PSII were monitored using different fluorescence parameters. Differences in responses between endosymbiotic algae of two P. bursaria strains – Ard7 from a warm climate and KD64 from a cold climate – were determined. The highest photosynthetic activity of P. bursaria green endosymbionts was observed at a temperature of 18°C, regardless of the light conditions. Algae from warm climate were more sensitive to cold temperature stress than algae from P. bursaria collected in cold climate.

Photosynthesis ecophysiology of polar Vaucheria sp. – inter-annual comparison

2019 ◽  
Vol 9 (2) ◽  
pp. 141-151
Author(s):  
Jana Kvíderová ◽  
Josef Elster
Keyword(s):  
Quantum Yield ◽  
Air Temperature ◽  
Microbial Mats ◽  
Photosynthetic Activity ◽  
Red Light ◽  
Ex Situ ◽  
Effective Quantum Yield ◽  
Excitation Light ◽  
Fluorescence Measurements ◽  
Arctic Summer

The Vaucheria sp. microbial mats represent the most important primary producer in the tidal flat in Adventdalen, Svalbard. Its photosynthetic activity was monitored ex situ in a microcosm in late Arctic summer in 2016 and 2017 using variable chlorophyll fluorescence measurements with blue and red excitation lights. The effective quantum yield (FPSII) was measured, and the photosynthetic relative electron transport rate (rETR) was calculated. During the measurement period, the microclimate data, air temperature and photosynthetically active radiation (PAR), were recorded as well. Year 2016 was slightly warmer than year 2017. Despite of higher maximum PAR values found in 2016, the mean irradiance reached higher values in 2017 than 2016. When using red light excitation, the rETR and effective quantum yield values were lower than those measured using blue excitation light in 2016. However, opposite results were recorded in 2017, indicating thus rather sample-specific differences. According to redundancy analysis, the PAR was confirmed as the main driver of photosynthesis in late Arctic summer in both years. No serious photoinhibition, expressed as serious systematic decline of the rETR, was observed in both years indicating rapid photoacclimation of Vaucheria sp. photosynthesis to changing light environment. The air temperature was found to be less important driver of the photosynthetic activity. The inter-annual comparisons showed increased photosynthetic activity in 2017, probably caused by higher PAR in 2017, by differences in microcosmos design and/or heterogeneity of samples.

scholarly journals Spectroscopic Studies of Dual Fluorescence in 2-(4-Fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thiadiazole: Effect of Molecular Aggregation in a Micellar System

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2861 ◽  
Author(s):  
Grzegorz Czernel ◽  
Arkadiusz Matwijczuk ◽  
Dariusz Karcz ◽  
Andrzej Górecki ◽  
Agnieszka Niemczynowicz ◽  
...  
Keyword(s):  
Light Scattering ◽  
Fluorescence Spectra ◽  
Single Photon ◽  
Spectroscopic Studies ◽  
Fluorescence Probes ◽  
Molecular Aggregation ◽  
Micellar System ◽  
Dual Fluorescence ◽  
Fluorescence Measurements ◽  
Ionic Detergent

The article presents the results of spectroscopic studies focused on a selected compound from the 1,3,4-thiadiazole group—2-(4-fluorophenylamino)-5-(2,4-dihydroxybenzeno)-1,3,4-thia-diazole (FABT)—in a micellar system formed by Triton X-100, a non-ionic detergent. Fluorescence measurements revealed the phenomenon of dual fluorescence whose emergence is related to the particular molecular organisation of the compound, which depends both on the concentration of the detergent and, most of all, the concentration of the compound itself. Dual fluorescence of FABT in a micellar system was observed for the compound dissolved in a methanol aqueous system, i.e., an environment wherein the dual fluorescence of the compound had never been reported before. Based on the interpretation of UV-Vis electronic absorption, resonance light scattering (RLS), emission and excitation fluorescence spectra, as well as measurements of dynamic light scattering (DLS) and Principal Component Analysis (PCA), we were able to relate the occurrence of this effect to the process of molecular aggregation taking place between FABT molecules in the micellar system in question. Results of fluorescence spectra measurements and time-correlated single photon counting (TCSPC) indicate that dual fluorescence occurs at detergent concentrations necessary to form micellar systems, which in turn facilitate the process of aggregation of FABT molecules. The correlation between the observed fluorescence effects and the previous measurements performed for analogues from this group suggests the possibility of charge transfer (CT) within the range of detergent concentrations wherein the aforementioned fluorescence effects are observed. It ought to be emphasised that this type of fluorescence effects are relatively easy to induce, which predisposes this groups of fluorophores as ideal fluorescence probes in the context of biological samples.

Is the in vivo Photosystem I Function Resistant to Photoinhibition? An Answer from Photoacoustic and Far-Red Absorbance Measurements in Intact Leaves

1991 ◽  
Vol 46 (11-12) ◽  
pp. 1038-1044 ◽  
Author(s):  
Michel Havaux ◽  
Murielle Eyletters
Keyword(s):  
Light Stress ◽  
Red Light ◽  
Light Treatment ◽  
High Light ◽  
Saturation Curve ◽  
Strong Light ◽  
Ps Ii ◽  
Fluorescence Measurements ◽  
Ps I

Abstract Preillumination of intact pea leaves with a strong blue-green light of 400 W m-2 markedly inhibited both photoacoustically monitored O2-evolution activity and PS II photochemistry as estimated from chlorophyll fluorescence measurements. The aim of the present work was to examine, with the help of the photoacoustic technique, whether this high-light treatment deteriorated the in vivo PS I function too. High-frequency photoacoustic measurements indicated that photochemical conversion of far-red light energy in PS I was preserved (and even transiently stimulated) whereas photochemical energy storage monitored in light exciting both PS I and PS II was markedly diminished. Low-frequency photoacoustic measurements of the Emerson enhancement showed a spectacular change in the PS II/PS I activity balance in favor of PS I. It was also observed that the linear portion of the saturation curve of the far-red light effect in the Emerson enhancement was not changed by the light treatment. Those results lead to the conclusion that, in contrast to PS II, the in vivo PS I photofunctioning was resistant to strong light stress, thus confirming previous suggestions derived from in vitro studies. Estimation of the redox state of the PS I reaction center by leaf absorbance measurements at ca. 820 nm suggested that, under steady illumination, a considerably larger fraction of PS I centers were in the closed state in high-light pretreated leaves as compared to control leaves, presumably allowing passive adjustment of the macroscopic quantum yield of PS I photochemis­ try to the strongly reduced photochemical efficiency of photoinhibited PS II.

scholarly journals Journal of Food Quality Thermal Degradation of Plum Anthocyanins: Comparison of Kinetics from Simple to Natural Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Mihaela Turturică ◽  
Nicoleta Stănciuc ◽  
Claudia Mureșan ◽  
Gabriela Râpeanu ◽  
Constantin Croitoru
Keyword(s):  
Antioxidant Activity ◽  
Citric Acid ◽  
Thermal Degradation ◽  
Fluorescence Spectra ◽  
Degradation Rate ◽  
Natural Systems ◽  
Degradation Rate Constant ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The Stability

The stability of anthocyanin was assessed over a temperature range of 50–120°C in different simulated plum juices in order to compare the thermal behavior in the presence of certain compounds. The results were correlated with the antioxidant activity and intrinsic fluorescence spectra. The results suggested significant changes, especially at higher temperature; hence, increase in the fluorescence intensity and some bathochromic and hypsochromic shifts were observed. Anthocyanins in natural matrices presented the highest rate for degradation, followed by the anthocyanins in juices with sugars. Values of the activation energies were 42.40 ± 6.87 kJ/mol for the degradation in water, 40.70 ± 4.25 kJ/mol for the juices with citric acid, 23.03 ± 3.53 kJ/mol for the juices containing sugars, 35.99 ± 3.60 kJ/mol for simulated juices with mixture, and 14.19 ± 2.39 kJ/mol for natural juices. A protective effect of sugars was evidenced, whereas in natural matrices, the degradation rate constant showed lower temperature dependence.

Is leaf age a predictor for cold tolerance in winter oilseed rape plants?

2020 ◽  
Vol 47 (3) ◽  
pp. 250 ◽  
Author(s):  
Ali Doǧru ◽  
Hüsnü Çakırlar
Keyword(s):  
Low Temperature ◽  
Oilseed Rape ◽  
Cold Exposure ◽  
Photosynthetic Activity ◽  
Leaf Age ◽  
Fluorescence Yield ◽  
Antioxidant Enzyme Activities ◽  
Winter Oilseed Rape ◽  
Fluorescence Measurements ◽  
Young Leaves

In the present study, low temperature-dependent physiological changes were investigated through photosynthetic activity and some endogenous mechanisms in two winter oilseed rape cultivars (Brassica napus L. ssp. oleifera cvv. Eurol and Hansen) on the basis of leaf age. Chlorophyll fluorescence measurements demonstrated that low temperature caused decreased photosynthetic activity in both cultivars. However, photosynthetic apparatus in the young leaves of Hansen is more tolerant to low temperature as demonstrated by lower F0 (minimum fluorescence yield) and 1–qp (excitation pressure of photosystem II), higher Fm (maximum fluorescence yield), Fv/Fm and non-photochemical quenching (NPQ) compared with Eurol. In addition, young leaves of Hansen represented marked increase in some antioxidant enzyme activities (superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR)) during cold exposure. In the young leaves of Eurol, however, APX and GR activity was decreased by low temperature, indicating lower efficiency of ascorbate-glutathione cycle. Lower antioxidant activity in the young leaves of Eurol may be responsible for increased malondialdehyde (MDA), H2O2 and membrane damage and decreased chlorophyll content as a result of oxidative damage during cold exposure. In the cold-stressed mature leaves, both cultivars represented similar antioxidant capacities and photosynthetic efficiency. As a consequence, coordinated increase in SOD, APX and GR activities, increased capacity to keep quinone A (QA) in an oxidised state (as indicated by lower 1–qp) and accumulation of soluble sugar and proline could be mainly attributed to higher level of tolerance of the young leaves of Hansen to low temperature when compared with Eurol.

scholarly journals Automatic cell identification and enrichment in lung cancer. II. Acridine orange for cell sorting of sputum.

1979 ◽  
Vol 27 (1) ◽  
pp. 552-556 ◽  
Author(s):  
H W Tyrer ◽  
J F Golden ◽  
M H Vansickel ◽  
C K Echols ◽  
J K Frost ◽  
...  
Keyword(s):  
Acridine Orange ◽  
Propidium Iodide ◽  
Cell Sorting ◽  
Fluorescence Spectra ◽  
Fluorescent Dyes ◽  
Appreciable Amount ◽  
Pleural Effusions ◽  
Green Fluorescence ◽  
Total Fluorescence ◽  
Cytoplasmic Differentiation

Fluorescence spectra were obtained from cells from sputum and pleural effusions stained with different fluorescent dyes and fixed by alternate methods. The spectra were referenced to a standard allowing for fluorescence comparisons of unstained and stained cells under various conditions. The metachromasia of acridine orange-stained cells offers nuclear/cytoplasmic differentiation in a single stain; mithramycin and propidium iodide do not. Unstained cells have an appreciable amount of green (546 nm) fluorescence, as does Carbowax in Saccomanno's preservative. Cytoplasm stained with acidine orange also has appreciable green fluorescence. Consequently, cells with much cytoplasm have high total fluorescence. Cytoplasmic fluorescence is negligible with mithramycin or propidium iodide. The metachromasia of acridine orange-stained cells is altered by alcohol and Carbowax levels in fixatives, keeping other factors constant.

A spectrofluorimetric method for the determination of acitretin in pharmaceuticals

2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Suling Feng ◽  
Yi Zhang ◽  
Jing Fan
Keyword(s):  
Fluorescence Spectra ◽  
Hplc Method ◽  
Relative Fluorescence Intensity ◽  
Optimum Conditions ◽  
Green Fluorescence ◽  
Spectrofluorimetric Method ◽  
Highly Sensitive ◽  
Relative Standard ◽  
Effects Of Ph

AbstractA simple, rapid, and highly sensitive spectrofluorimetric method for the determination of acitretin was developed based on the strong green fluorescence of acitretin. Influence of organic solvents on the fluorescence spectra of acitretin was studied. Effects of pH, standing time, and foreign ions on the determination of acitretin were also examined. Under the optimum conditions, linear relationship between the relative fluorescence intensity and the concentration of acitretin in the range of 30.0–1100 ng mL−1 was obtained. Detection limit of this method is 9.56 ng mL−1 for acitretin. Relative standard deviation for the determination of 480 ng mL−1 of acitretin was 1.70 %. This method was used for the determination of acitretin in pharmaceuticals and the results were compared with those obtained by the HPLC method.

Temperature Dependence of Minority Carrier Lifetimes in a-Si:H

1996 ◽  
Vol 420 ◽  
Author(s):  
J. C. L. Cornish ◽  
Subaer ◽  
P. Jennings ◽  
G. T. Hefter
Keyword(s):  
Minority Carrier ◽  
Red Light ◽  
Open Circuit ◽  
Xenon Lamp ◽  
Carrier Lifetimes ◽  
Minority Carrier Lifetimes ◽  
Higher Temperature ◽  
Straight Lines ◽  
Deposited Films ◽  
Trap Activation

AbstractChanges in minority carrier lifetimes in a-Si:H, p-i-n photovoltaic cells due to light soaking have been investigated using the open circuit voltage decay (OCVD) method over the temperature range 223 K to 296 K.Using light from a Xenon flash lamp for excitation produced unexpected results: in the light soaked material, band-to-band transitions were evident at a higher temperature than for the asdeposited samples and became increasingly pronounced as the temperature was reduced. Results obtained using red light at 670 nm from a pulsed diode laser to produce relatively uniform- illumination throughout the thickness of the film, however, produced results very similar to those obtained for as-deposited films.Plots of the reciprocal of the trap activation time versus 1000/T for the results for both xenon lamp and laser excitation can be fitted by straight lines. Two distinct sets of lines with activation energies in the ranges 0.07 to 0.20 eV and 0.38 to 0.51 eV are obtained with the activation energy and the exponential prefactors exhibiting a Meyer-Neldel relationship.

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