Extraction and quantification of phosphorus derived from DNA and lipids in environmental samples

Paraskova, Julia V.; Rydin, Emil; Sjöberg, Per J. R.

doi:10.1016/j.talanta.2013.05.042

Cited by 16 publications

(5 citation statements)

References 28 publications

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“…Phosphorus analysis was performed as described by Paraskova et al with the modication that the digestion was performed solely by dry ashing at 550 C for 4 h (other steps of the digestion were considered redundant). 25 In case of lipodisk production by means of SEC, the recovered proportions of the DPPC and cholesterol components were determined from experiments in which 3 H-DPPC and 3 Hcholesterol, respectively, were included in the preparations. The radioactivity in aliquots of the original sample and the fractions collected aer SEC were assessed by means of measurements using the scintillator counter specied above.…”

Section: Quantication Of Curcumin and Lipid Contentmentioning

confidence: 99%

EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells

et al. 2017

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Concerns regarding poor aqueous solubility, high toxicity and lack of specificity impede the translation of many hydrophobic anticancer agents into safe and effective anticancer drugs. The application of colloidal drug delivery systems, and in particular the use of lipid-based nanocarriers, has been identified as a promising means to overcome these issues. PEG-stabilized lipid nanodisks (lipodisks) have lately emerged as a novel type of biocompatible, nontoxic and adaptable drug nanocarrier. In this study we have explored the potential of lipodisks as a platform for formulation and tumour targeted delivery of hydrophobic anticancer agents. Using curcumin as a model compound, we show that lipodisks can be loaded with substantial amounts of hydrophobic drugs (curcumin/lipid molar ratio 0.15). We demonstrate moreover that by deliberate choice of preparation protocols the lipodisks can be provided with relevant amounts of targeting proteins, such as epidermal growth factor (EGF). Data from in vitro cell studies verify that such EGF-decorated curcumin-loaded lipodisks are capable of EGF-receptor specific targeting of human A-431 tumour cells, and strongly suggest that the interaction between the lipodisks and the tumour cells results in receptor-mediated internalization of the disks and their cargo.

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Section: Quantication Of Curcumin and Lipid Contentmentioning

confidence: 99%

EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells

et al. 2017

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“…This choice was motivated by the fact that phosphocholine lipids with asymmetric acyl chains are both the most common lipid in eukaryotic membranes and frequently used in the creation of artificial model membranes. Additionally, POPC and the dye–lipid conjugates (NBD-PE and Rho-PE) are all phospholipids whose concentrations in the final working solutions could be accurately quantified orthogonally using the molybdenum blue method for phosphorus quantification, thereby making it possible to account for the potential material loss during vesicle preparation and thus to ensure that the established calibration curve was accurate. The acceptor fluorophore content in the FRET liposomes was set to 0.5 mol %, i.e., in the range where the change in FRET efficiency is most sensitive to changes in acceptor surface density …”

Section: Resultsmentioning

confidence: 99%

“…To quantify the phospholipid content of the liposome stocks prepared as described above and to account for possible lipid losses during the extrusion procedure, a phosphorus assay was used. The assay is based on the molybdenum blue method , and was performed as described by Paraskova et al with the modification that digestion was performed solely by dry ashing for at least 4 h at 550 °C. Calcination was performed in a Carbolite CWF 1200 furnace (Carbolite Gero Limited, Hope Valley, U.K.).…”

Section: Methodsmentioning

confidence: 99%

FRET-Based Assay for the Quantification of Extracellular Vesicles and Other Vesicles of Complex Composition

et al. 2020

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Research in the field of extracellular vesicles is rapidly expanding and finding footholds in many areas of medical science. However, the availability of methodologies to quantify the concentration of membrane material present in a sample remains limited. Herein, we present a novel approach for the quantification of vesicle material, specifically the quantification of the total lipid membrane surface area, found in a sample using Forster resonance energy transfer (FRET). In this assay, sonication is used to drive the fusion between vesicles in the sample to be quantified and liposomes containing a pair of FRET fluorophores. The change in emission spectrum upon vesicle fusion is directly related to the total membrane surface area of the sample added, and a calibration curve allows for the quantification of a variety of vesicle species, including enveloped viruses, bacterial outer membrane vesicles, and mammalian extracellular vesicles. Without extensive optimization of experimental parameters, we were able to quantify down to ∼10 9 vesicles/mL, using as little as 60 μL of the sample. The assay precision was comparable to that of a commercial nanoparticle tracking analysis system. While its limit of detection was slightly higher, the FRET assay is superior for the detection of small vesicles, as its performance is vesicle-size-independent. Taken together, the FRET assay is a simple, robust, and versatile method for the quantification of a variety of purified vesicle samples.

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“…Then, P concentrations were determined spectrophotometrically (Murphy and Riley 1962). This method has a detection limit of about 3 ng P mL −1 with a precision below 10% RSD (Paraskova et al 2013). The inositol‐P identification, consisting of tri‐ to hexainositols (I‐P3, I‐P4, I‐P5, and I‐P6), includes a single extraction step using 0.25 mol L −1 NaOH containing 0.050 mol L −1 EDTA, shaking, and centrifugation at 10,000 rpm before being placed in an LC autosampler for analysis.…”

Section: Methodsmentioning

confidence: 99%

Contrasting distribution and speciation of sedimentary organic phosphorus among different basins of the Baltic Sea

Rydin

Broman

Reitzel

et al. 2023

Limnology & Oceanography

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Recycling of phosphorus (P) from deoxygenated sediments perpetuates eutrophic conditions in parts of the Baltic Sea. Sedimentary organic P is a major source of dissolved P to the water column, but also a sink for permanent P burial. The mechanisms behind these two pathways are, however, largely unknown. Using new methods, we determined P in DNA and phospholipids, which are both found in all organisms. We also identified inositol phosphates that are particularly important in eukaryotes. Sediment cores were collected from contrasting basins in the Baltic Sea to study their relative contribution to the total P pool. We found high DNA-P/phospholipid-P ratios in surface sediments from the Bothnian Bay and Bothnian Sea. However, these ratios were low throughout profiles in euxinic Baltic Proper sediments. The elevated ratios present in sediments overlain by oxic bottom waters might indicate the presence of a microbial community stimulated by bioturbation, whereas the low DNA-P/phospholipid-P ratios in Baltic Proper sediments likely indicate an energy-limited microbial community, typical to the "deep biosphere" environment. Inositol-P was almost absent in euxinic Baltic Proper sediments that had a low total P amount compared to those in the other basins. We suggest that variability in the composition of sedimentary microbial communities among the Baltic Sea basins might cause differences in organic P forms that in turn affects its turnover.

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Extraction and quantification of phosphorus derived from DNA and lipids in environmental samples

Cited by 16 publications

References 28 publications

EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells

EGF-targeting lipodisks for specific delivery of poorly water-soluble anticancer agents to tumour cells

FRET-Based Assay for the Quantification of Extracellular Vesicles and Other Vesicles of Complex Composition

Contrasting distribution and speciation of sedimentary organic phosphorus among different basins of the Baltic Sea

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