Before plants were harvested, another 0.5 g root sample was taken to measure acid phosphatase (APase). Root samples were washed in deionized water four times. The APase activity on the root surface was analyzed according to Neumann et al. (1999) (link). Root samples were placed in a centrifuge tube with 0.4 mL substrate buffer (pH 5.2); then 0.1 mL p-nitrophenyl phosphate (NPP) was added and 0.5 mL deionized water. Centrifuge tubes were placed in a 30°C water bath for 15 min, and then 0.5 mL 0.5 M NaOH was added to terminate the reaction and develop the color. The absorbance of the resulting color was determined spectrophotometrically (UV-2201, Shimadzu, Kyoto, Japan) at 405 nm.
Uv 2201
Manufactured by Shimadzu
Sourced in Japan
The UV-2201 is a UV-Vis spectrophotometer manufactured by Shimadzu. It is designed to measure the absorption of ultraviolet and visible light by samples, providing information about their chemical composition and concentration.
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Lab products found in correlation
3 protocols using uv 2201
1
Measuring Root Surface Acid Phosphatase
2
Quantifying Proteoglycan Content in Intervertebral Discs
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At 24 weeks, IVD samples from L6–L7, together with the adjacent AF and surrounding soft tissue, were resected and fixed in 20% formalin for the determination of PG content. In a preliminary experiment, PG content was slightly reduced with no statistical significance at 4 and 8 weeks; however, levels were significantly attenuated at 12 weeks22 (link). After degreasing, 10 mg of NP were added to 0.05 mL of 3% NaOH in a 4-mL centrifuge tube, which was incubated at 40 °C in a water bath using a constant temperature vibrator for 3 h. Then, 2 mL of glacial acetic acid and 50 μL of 0.25% trypsin was added to the tube, which was further incubated at 50 °C in a water bath for 2 h. The enzyme mixture was transferred to a flask and divided into 10-mL aliquots. One milliliter of this solution was used for PG analysis according to the phloroglucinol method20 (link). Absorbance of the reaction mixture was detected using a spectrophotometer (UV-2201; Shimadzu Corporation, Tokyo, Japan) at a wavelength of 558 nm, then transformed into PG content.
3
In Vitro Release Kinetics of Gastrodin and Borneol from Sustained-Release Solid Dispersions
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The drug release tests of the SRSDs were carried out by the paddle method specified in the Chinese Pharmacopoeia at a paddle rotation speed of 100 rpm in 900 mL distilled water at 37±0.5 °C. The SRSDs were weighed so as to contain 20 mg of gastrodin. At the specified time (0.5, 1, 2, 4, 6 and 8 h), 8 mL of the dissolution medium was sampled, and fresh medium (8 mL) prewarmed at 37 °C was simultaneously added to the dissolution medium to maintain a constant volume throughout the test. The sample was filtered with a membrane filter (0.45 μm). Aliquots of 2.5 mL were withdrawn and assayed for borneol content by gas chromatograph (GC-122, Factory of Analytical Apparatus, Shanghai, China)19 . The remaining filtrate was assayed for gastrodin content by measuring the absorbance at 221 nm on a UV–visible spectrophotometer (UV2201, Shimadzu, Japan).
To analyze the in vitro release data, various kinetic models including the zero-order model (Eq.(1) ), the first-order model (Eq. (2) ) and the Higuchi model (Eq. (3) ) were used to describe the release kinetics20 (link).
In these equations, R and UR are the released and unreleased percentages at time (t) and k is the rate constant.
To analyze the in vitro release data, various kinetic models including the zero-order model (Eq.
In these equations, R and UR are the released and unreleased percentages at time (t) and k is the rate constant.
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