scholarly journals Dihydrodinophysistoxin-1 Produced by Dinophysis norvegica in the Gulf of Maine, USA and Its Accumulation in Shellfish

Toxins ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 533
Author(s):  
Jonathan R. Deeds ◽  
Whitney L. Stutts ◽  
Mary Dawn Celiz ◽  
Jill MacLeod ◽  
Amy E. Hamilton ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Gulf Of Maine ◽  
High Resolution Mass Spectrometry ◽  
Shellfish Poisoning ◽  
Biological Source ◽  
Management Guidance ◽  
Liquid Chromatography Tandem Mass ◽  
Protein Phosphatase Inhibition ◽  
Multiple Species

Dihydrodinophysistoxin-1 (dihydro-DTX1, (M-H)−m/z 819.5), described previously from a marine sponge but never identified as to its biological source or described in shellfish, was detected in multiple species of commercial shellfish collected from the central coast of the Gulf of Maine, USA in 2016 and in 2018 during blooms of the dinoflagellate Dinophysis norvegica. Toxin screening by protein phosphatase inhibition (PPIA) first detected the presence of diarrhetic shellfish poisoning-like bioactivity; however, confirmatory analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS) failed to detect okadaic acid (OA, (M-H)−m/z 803.5), dinophysistoxin-1 (DTX1, (M-H)−m/z 817.5), or dinophysistoxin-2 (DTX2, (M-H)−m/z 803.5) in samples collected during the bloom. Bioactivity-guided fractionation followed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) tentatively identified dihydro-DTX1 in the PPIA active fraction. LC-MS/MS measurements showed an absence of OA, DTX1, and DTX2, but confirmed the presence of dihydro-DTX1 in shellfish during blooms of D. norvegica in both years, with results correlating well with PPIA testing. Two laboratory cultures of D. norvegica isolated from the 2018 bloom were found to produce dihydro-DTX1 as the sole DSP toxin, confirming the source of this compound in shellfish. Estimated concentrations of dihydro-DTX1 were >0.16 ppm in multiple shellfish species (max. 1.1 ppm) during the blooms in 2016 and 2018. Assuming an equivalent potency and molar response to DTX1, the authority initiated precautionary shellfish harvesting closures in both years. To date, no illnesses have been associated with the presence of dihydro-DTX1 in shellfish in the Gulf of Maine region and studies are underway to determine the potency of this new toxin relative to the currently regulated DSP toxins in order to develop appropriate management guidance.

scholarly journals Comparison of Liquid Chromatography/Mass Spectrometry, ELISA, and Phosphatase Assay for the Determination of Microcystins in Blue-Green Algae Products

2001 ◽  
Vol 84 (4) ◽  
pp. 1035-1044 ◽  
Author(s):  
James F Lawrence ◽  
Barbara Niedzwiadek ◽  
Cathie Menard ◽  
Benjamin P Y Lau ◽  
David Lewis ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Green Algae ◽  
Solid Phase ◽  
Enzyme Linked Immunosorbent Assay ◽  
Blue Green Algae ◽  
Biochemical Assays ◽  
Liquid Chromatography Tandem Mass ◽  
Protein Phosphatase Inhibition ◽  
Phosphatase Assay

Abstract More than 100 samples of blue-green algae products (consisting of Aphanizomenon, Spirulina, and unidentified blue-green algae) in the form of pills, capsules, and powders were collected from retail outlets from across Canada. The samples were extracted with 75% methanol in water and centrifuged to remove solids. Aliquots of the extracts along with spiked blank sample extracts were sent to each participating laboratory and independently analyzed for microcystins by enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assay, and by liquid chromatography–tandem mass spectrometry (LC–MS/MS) after sample cleanup using C18 solid–phase extraction. The results obtained by ELISA and LC–MS/MS agreed very well over a concentration range of about 0.5–35 μg/g. The colorimetric phosphatase results generally agreed with the other 2 methods. While the 2 biochemical assays measured total microcystin content compared with a standard of microcystin LR, the LC–MS/MS method measured specific microcystins (LA, LR, RR, YR) using external standards of these for identification and quantitation. Microcystin LR was found in all positive samples by LC–MS/MS. Microcystin LA was the only other microcystin found in the samples analyzed. These 2 microcystins represent essentially all the microcystins that were present in the extracts. Otherwise, the LC–MS/MS results would have been significantly lower than the results of the biochemical assays had other unknown microcystins been present.

scholarly journals Investigation of Bemethyl Biotransformation Pathways by Combination of LC–MS/HRMS and In Silico Methods

2021 ◽  
Vol 22 (16) ◽  
pp. 9021
Author(s):  
Daria A. Belinskaia ◽  
Elena I. Savelieva ◽  
Georgy V. Karakashev ◽  
Olga I. Orlova ◽  
Mikhail A. Leninskii ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
In Silico ◽  
High Performance ◽  
High Resolution Mass Spectrometry ◽  
Monitoring Program ◽  
Urinary Metabolites ◽  
Rat Urine ◽  
In Silico Studies ◽  
Liquid Chromatography Tandem Mass

Bemethyl is an actoprotector, an antihypoxant, and a moderate psychostimulant. Even though the therapeutic effectiveness of bemethyl is well documented, there is a gap in knowledge regarding its metabolic products and their quantitative and qualitative characteristics. Since 2018, bemethyl is included to the Monitoring Program of the World Anti-Doping Agency, which highlights the challenge of identifying its urinary metabolites. The objective of the study was to investigate the biotransformation pathways of bemethyl using a combination of liquid chromatography-high-resolution mass spectrometry and in silico studies. Metabolites were analyzed in a 24 h rat urine collected after oral administration of bemethyl at a single dose of 330 mg/kg. The urine samples were prepared for analysis by a procedure developed in the present work and analyzed by high performance liquid chromatography–tandem mass spectrometry. For the first time, nine metabolites of bemethyl with six molecular formulas were identified in rat urine. The most abundant metabolite was a benzimidazole–acetylcysteine conjugate; this biotransformation pathway is associated with the detoxification of xenobiotics. The BioTransformer and GLORY computational tools were used to predict bemethyl metabolites in silico. The molecular docking of bemethyl and its derivatives to the binding site of glutathione S-transferase has revealed the mechanism of bemethyl conjugation with glutathione. The findings will help to understand the pharmacokinetics and pharmacodynamics of actoprotectors and to improve antihypoxant and adaptogenic therapy.

scholarly journals Implication of Opioid Receptors in the Antihypertensive Effect of a Novel Chicken Foot-Derived Peptide

Biomolecules ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 992
Author(s):  
Anna Mas-Capdevila ◽  
Lisard Iglesias-Carres ◽  
Anna Arola-Arnal ◽  
Gerard Aragonès ◽  
Begoña Muguerza ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Opioid Receptors ◽  
High Performance ◽  
Antihypertensive Effect ◽  
High Resolution Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass

The peptide AVFQHNCQE demonstrated to produce nitric oxide-mediated antihypertensive effect. This study investigates the bioavailability and the opioid-like activity of this peptide after its oral administration. For this purpose, in silico and in vitro approaches were used to study the peptide susceptibility to GI digestion. In addition, AVFQHNCQE absorption was studied both in vitro by using Caco-2 cell monolayers and in vivo evaluating peptide presence in plasma from Wistar rats by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and by ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Both in vivo and in vitro experiments demonstrated that peptide AVFQHNCQE was not absorbed. Thus, the potential involvement of opioid receptors in the BP-lowering effect of AVFQHNCQE was studied in the presence of opioid receptors-antagonist Naloxone. No changes in blood pressure were recorded in rats administered Naloxone, demonstrating that AVFQHNCQE antihypertensive effect is mediated through its interaction with opioid receptors. AVFQHNCQE opioid-like activity would clarify the antihypertensive properties of AVFQHNCQE despite its lack of absorption.

scholarly journals Method of extraction and proteome profiling of mycobacteria using liquid chromatography-high resolution mass spectrometry

2020 ◽  
Vol 2 (11) ◽  
Author(s):  
Amol Bajaj ◽  
Suraj Saraswat ◽  
Joanna Freeke ◽  
Adam Barker
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Protein Identification ◽  
High Resolution Mass Spectrometry ◽  
Massively Parallel Sequencing ◽  
Protein Profile ◽  
Cell Lysis ◽  
Mycolic Acid ◽  
Extraction Solvent ◽  
Liquid Chromatography Tandem Mass

AbstractAdvances in massively parallel sequencing, of complete bacterial genomes, have led to many novel findings in the field of genomics. However, these data often lack correlation with expressed protein profiles. It has been demonstrated that even very closely related genomes, such as in mycobacteria, express drastically different phenotypes. These phenotypes often have major roles in pathogenicity. Therefore, it is just as important to have a method for examining the proteome of a bacterium as well as its genome. These studies are further complicated in mycobacteria due to the cell wall and mycolic acid. A comprehensive method for the identification and characterization of the whole mycobacterium protein profile is needed. In the present study, a simple, sensitive, and specific liquid chromatography tandem mass spectrometry method was developed for the extraction, purification and profiling the mycobacterial proteome in various species. During development, sonication and bead-beating cell lysis protocol was tested using 15% Acetonitrile and 6 M guanidine-HCl (GuHCl) as extraction solvent. Sonication lysis in 6 M GuHCl with glass beads was the preferred method for cell lysis. This method was developed using reverse phase liquid chromatography and a Q Exactive ™ Plus Orbitrap™ mass spectrometer for peptide and protein identification. Bottom-up liquid chromatography-mass spectrometry LC–MS analysis resulted in identification of greater than 2500 proteins.

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