The effects of the magnesium ions were evaluated by mean of spectrophotometric method as reported45 (link), using a Ultrospec 2100 pro UV-Vis spectrophotometer (Amersham Biosciences) and Hellma quartz cuvette with 1 cm optical path. MgCl2 1 M solution was prepared from powder (Carlo Erba Reagents, Milano, Italy). Each studied compound was dissolved in DMSO to a final concentration of 10 mM and diluted in milliQ water to a final concentration of 100 µM. Each obtained solution was placed in a cuvette and the UV-Vis and the spectra were recorded between 200 and 700 nm using water milliQ (with a percentage of DMSO equal to the one present in the sample solution) as reference. Thereafter, small volumes of MgCl2 aqueous solution were added both in the sample and in the reference cuvettes to obtain a series of solutions containing increasing concentrations of MgCl2, up to 1.25 mM, carefully pipetting to mix, and the UV-Vis spectra were repeated. Each experiment was performed in triplicate.
Ultrospec 2100 pro uv vis spectrophotometer
Manufactured by Cytiva
Sourced in United Kingdom
The Ultrospec 2100 pro UV-Vis spectrophotometer is a compact, high-performance instrument designed for accurate absorbance measurements across the UV-Visible spectrum. It features a wide wavelength range, high-resolution optics, and a user-friendly interface.
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13 protocols using ultrospec 2100 pro uv vis spectrophotometer
1
Spectrophotometric Analysis of Magnesium Effects
2
Cultivation and Transformation of Synechococcus elongatus
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S. elongatus cultures were routinely grown at 30 °C in BG11 media (BG110 plus 17.5 mM sodium nitrate (NaNO3) and 10 mM HEPES/NaOH pH 7.8; [41 (link)]), under constant illumination provided by cool white-fluorescent lights in baffled flasks (shaking: 150 rpm, 70 μmol photons m−2s−1) or on plates (50 μmol photons m−2s−1). For solid media, 1.5% (w/v) agar and 0.5 mM sodium thiosulfate (Na2S2O3; after autoclaving) were added. Transformations were performed essentially as described [42 (link)]. To select genetically modified strains, solid media were supplemented with the antibiotics chloramphenicol (Cm; 3.5 μg mL−1), streptomycin (Sm; 15 μg mL−1), or kanamycin (Km; 12 μg mL−1).
To initiate liquid cultures, strains were inoculated into 30 mL of BG11 and incubated under standard conditions for two days. Subsequently, culture stocks were adjusted to an initial optical density (OD750nm) of 0.1 and grown until they reached 0.5–0.7 in 25–30 mL. Optical density was measured in an Ultrospec 2100 pro UV–Vis Spectrophotometer (Amersham, Buckinghamshire, UK). For light transition experiments, cultures at an OD750nm of 0.7 were subjected to 12 h of darkness before being transferred to light.
To initiate liquid cultures, strains were inoculated into 30 mL of BG11 and incubated under standard conditions for two days. Subsequently, culture stocks were adjusted to an initial optical density (OD750nm) of 0.1 and grown until they reached 0.5–0.7 in 25–30 mL. Optical density was measured in an Ultrospec 2100 pro UV–Vis Spectrophotometer (Amersham, Buckinghamshire, UK). For light transition experiments, cultures at an OD750nm of 0.7 were subjected to 12 h of darkness before being transferred to light.
3
Spectroscopic Analysis of GSH and Molybdate
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Stock solutions of reduced GSH (Duchefa, Harlem, Netherlands) and sodium molybdate (Sigma-Aldrich, St. Louis, MI, USA) were prepared in water with a concentration of 2 mM. The 2 mM GSH sample was diluted with water to a concentration of 1 mM. The spectrum of each sample was recorded by measuring the extinction of light in the UV region ranging from 190 nm to 350 nm in special UV cuvettes with a layer thickness of 1 cm using an Ultrospec 2100 pro UV/VIS spectrophotometer (Amersham Biosciences, Amersham, UK). Subsequently, the background of a sodium molybdate solution with a concentration of 1 mM was subtracted from the spectrum by blanking. The GSH and molybdate solution was mixed equimolar to a concentration of 1 mM each and the extinction spectrum was recorded.
4
Quantifying FITC Dye Encapsulation in NPs
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To study the EE for FITC dye, 5 mg of dry NPs was dissolved in 0.8 M NaOH, as described above. The separate solutions containing PLGA-PEG and PLGA-PEG-TFA NPs were centrifugated at 12,000 rpm for 20 min at room temperature, and the supernatants were collected. The FITC dye content was then measured using an Amersham Biosciences Ultrospec 2100 pro, UV/Vis Spectrophotometer. The amount of FITC dye was calculated from the linear regression of the standard curve obtained from the FITC solution.
5
Fluorescence Spectroscopy of TEDG
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A Hitachi F-7000 spectrofluorometer was used to measure the emission and excitation spectra of TEDG samples in different solvents. The sample temperature was controlled using an external water bath. Absorption spectra were obtained using an Ultrospec 2100 pro UV-Vis spectrophotometer (Amersham Pharmacia).
6
Quantifying Released Antimicrobial Agents
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Material samples (disks of 1 cm in diameter) consisting of AA, AA–AgNO3, AA–QACs and AA–AgNO3–QACs were immersed in 1 mL of nanopure water for a predetermined duration ranging from 30 s to 144 h. At each time point, the solution was collected, and the absorbance was measured at a wavelength of 215 nm using a UV-VIS spectrophotometer (Ultrospec 2100 pro UV-VIS Spectrophotometer, Amersham Biosciences, UK). Calibration curves obtained by measuring the absorbance at 215 nm of several dilutions of the QACs stock solution showed linear behavior and were used to calculate the concentrations of QACs released from the materials.
7
Chlorophyll and Carotenoid Quantification
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Chlorophylls a and b and total carotenoids were extracted and quantified spectrophotometrically (Ultrospec 2100 pro-UV–vis spectrophotometer, Amersham Biosciences) from three groups of five plants per group, following the method reported by Wellburn (1994 (link)) with few modifications. In brief, 150-mg samples were homogenized with 80% (w/v) cold acetone before being centrifuged (5500 × g per 5 min at 4 °C), and the supernatant was collected. A second volume of 80% cold acetone was added to the pellet, centrifuged (5500 × g per 5 min at 4 °C), and the resulting supernatant was combined with the first. This procedure was repeated until the supernatant after centrifugation was clear. The absorbance of the combined supernatant was read at 663, 648, and 470 nm.
8
Quantification of SOD1 and SOD2 Activities
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SOD1 and SOD2 activities were assayed in all the samples according to de Haan et al (29 (link)) and as previously modified by us (30 (link)). Total SOD activity was measured by the addition of previously 1:10 diluted plasma (250 µl), blood hemolysate (100 µl) or placental tissue supernatant (50 µl) to xanthine (25 µl, 1.142 mg/ml), hydroxyl ammonium chloride (25 µl), water (125 µl) and xanthine oxidase (0.1 U/ml, 75 µl). The mixture was then incubated at 25°C for 20 min, and sulphonilic acid (0.5 ml, 3.3 mg/ml) and α-naphthylamine (0.5 ml, 1 ng/ml) were added and further incubated at a room temperature of 25°C for 20 min and absorbance was read at 530 nm using an Ultrospec 2100 pro UV/VIS Spectrophotometer (Amersham Biosciences, Piscataway, NJ, USA). The addition of potassium cyanide (125 µl, 4 mM) instead of water specifically inhibited SOD1 activity. Thus, subtraction of the activity remaining after the addition of potassium cyanide (SOD2) from total SOD activity yielded SOD1 activity.
9
Characterization of Fungal Laccase Samples
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All the reagents were of the best grade available, and were used without any further purification. The sole exception was fungal laccase (LC), and LC was produced and purified as already described [51 (link)] UV–Vis spectra and absorbance readings were recorded using an Ultrospec 2100pro UV–VIS spectrophotometer (Amersham Biosciences, Milan, Italy).
FT-IR spectra were recorded after the samples were prepared as KBr pellets, with a KBr beam-splitter and KBr windows using a Thermo Nicolet 5700 (Waltham, MA, USA) spectrometer at room temperature.
Sample morphology was observed using scanning electron microscopy (SEM) (S-4100, Hitachi, Tokyo, Japan). The samples were fixed on a brass stub using double-sided carbon coated with gold blazers on a SCD 004 sputter coater (Hitachi, Tokyo, Japan) for 2 min and observed under an excitation voltage of 5 kV.
FT-IR spectra were recorded after the samples were prepared as KBr pellets, with a KBr beam-splitter and KBr windows using a Thermo Nicolet 5700 (Waltham, MA, USA) spectrometer at room temperature.
Sample morphology was observed using scanning electron microscopy (SEM) (S-4100, Hitachi, Tokyo, Japan). The samples were fixed on a brass stub using double-sided carbon coated with gold blazers on a SCD 004 sputter coater (Hitachi, Tokyo, Japan) for 2 min and observed under an excitation voltage of 5 kV.
10
Quantifying Phenols and Flavonoids in Leaf and Root Samples
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Frozen samples of leaves leaf and roots samples were extracted following the method of by Becatti et al. (2010) . To determine the total phenol amount in both control and irradiated samples, the Folin-Ciocalteu method (Barbolan et al., 2003) was carried out performed recording the absorbance at 750 nm by an Ultrospec 2100 pro-UV-vis spectrophotometer (Amersham Biosciences). Total phenols were expressed as µg of gallic acid equivalents g -1 FW.
Total flavonoids were determined referring to Kim et al. (2003) recording the absorbance at 510 nm and their concentration was expressed as µg of catechin equivalents g -1 FW.
For both phenol and flavonoid assays, a standard curve was calculated using the corresponding commercial standards (Sigma-Aldrich Chemical Co., St. Louis, MO, USA).
Total flavonoids were determined referring to Kim et al. (2003) recording the absorbance at 510 nm and their concentration was expressed as µg of catechin equivalents g -1 FW.
For both phenol and flavonoid assays, a standard curve was calculated using the corresponding commercial standards (Sigma-Aldrich Chemical Co., St. Louis, MO, USA).
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