Protein in marine plankton: A comparison of spectrophotometric methods

Protein Extractions from Amphistegina lessonii: Protocol Development and Optimization

“…The Lowry and BCA methods are, therefore, the most accurate protein measurement approaches in benthic foraminifera (i.e., Amphistegina ). These findings are consistent with the outcomes of Martínez et al [ 5 ] that among all seven tested methodologies involving colorimetric protein assays (i.e., Rutter, Rutter-SDS, Markwell, BCA, microBCA, Bradford, and microBradford) on different sizes of marine plankton, a mysid, and a jellyfish species, determined the BRAD and mBRAD as methods consistently underestimating protein. The same results were obtained in a wide range of marine organisms, from bacteria to algae [ 25 , 26 ].…”

“…Phytoplankton, zooplankton, and benthic organisms are among marine groups that have been targeted for protein content analyses, although using different and sometimes incomparable techniques [ 5 ]. Protein analysis has recently found a new application area in the biomonitoring (i.e., pollution) or evaluation of climatic change effects (e.g., warming, acidification).…”

“…The methodologies used for protein assay in foraminifera have been inherited from traditional methods. However, the wide variety of such methods from extraction to staining makes it rather difficult to compare the results [ 5 ]. Indeed, no comparative tests on the reliability and performance of the different assays have been performed on foraminifera so far.…”

Wind Drifting vs. Pulsating Swimming Jellyfish: Respiratory Metabolism and Composition Differences in Physalis physalis, Velella velella, Aurelia aurita, and Pelagia noctiluca

“…The analysis was based on the Biuret reaction as described by Lowry et al (1951) and modified by Rutter (1967). It was further modified in this study by the addition of Dodecyl sulfate sodium salt (SDS) as suggested by Markwell et al (1978) and Martínez et al (2020). The lipid content was measured in samples homogenized previously without any further dilution.…”

Metabolic Responses of Subtropical Microplankton After a Simulated Deep-Water Upwelling Event Suggest a Possible Dominance of Mixotrophy Under Increasing CO2 Levels

“…We measured biomass (B) spectrophotometrically as particulate protein on the same homogenates used for the enzyme activity assays. We followed the protein method of Lowry et al (1951) as modified by Rutter (1967) and Martínez et al (2020) with bovine serum albumin (BSA) as the standard for calibration. This method consisted of a chemical reaction, where 200 µL of the supernatant of the centrifuged homogenate (see section 2.2): (1) was mixed with 1 mL of the "Rutter" solution (110 mL of a solution of 0.19 M Na 2 CO 3 , 0.10 M NaOH, and 0.71 mM Na-K tartrate, mixed with 2.2 mL of a solution of 0.02 M CuSO 4 •5H 2 O) in a cuvette stored in ice; (2) then mixed, after 10 min, with 100 µL of Folin's reagent (C 10 H 5 NaO 5 S, diluted 1:1 in doubled-distilled H 2 O) at laboratory temperature (22 • C); and (3) after being stored in darkness for 40 min at 22 • C, was pipetted into 1 cm path-length cuvette, inside the Cary100 UV-Vis Spectrophotometer (Agilent Technologies) to measure the absorbance at 750 nm.…”