Pub Date : 2022-10-13DOI: 10.3389/frans.2022.954915
H. Fiedler, Abeer Baabish, Mohammad Sadia
Perfluoroalkane substances (PFAS) comprise a large family of chemicals of environmental concern and are subject to chemical analyses, international regulation, and risk assessments. Environmental samples including air, water, sediment, and soil as abiotic matrices, food samples comprising fish, meat (beef, sheep, chicken), egg, butter, and milk as well as human milk samples were assessed using uni- and multivariate methods. Participating countries were asked to provide baseline samples and not target potential hotspots. Chemometric analysis was possible for only three of the 15 PFAS monitored, namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS). The assessments showed that PFAS contamination in developing countries and in all matrices considered was almost equally attributed to PFOS and PFOA; PFHxS did not play a role. Subsequently, across all samples, PFOS and PFOA were strongly negatively correlated (spearman correlation coefficient r = −0.94). The measured values showed moderate positive correlation between PFOS and PFOA (r = 0.76) indicating common sources or environmental behavior. No clear pattern could be observed for geographic locations nor for transfers between matrices. Whereas the abiotic samples—soil, sediment, air—gave a very heterogenous picture (very small p-values) and had wide ranges and outliers, the measured values of the biota samples were not significantly different between matrices.
{"title":"Multivariate analysis of abiotic and biota samples for three perfluoroalkane acids","authors":"H. Fiedler, Abeer Baabish, Mohammad Sadia","doi":"10.3389/frans.2022.954915","DOIUrl":"https://doi.org/10.3389/frans.2022.954915","url":null,"abstract":"Perfluoroalkane substances (PFAS) comprise a large family of chemicals of environmental concern and are subject to chemical analyses, international regulation, and risk assessments. Environmental samples including air, water, sediment, and soil as abiotic matrices, food samples comprising fish, meat (beef, sheep, chicken), egg, butter, and milk as well as human milk samples were assessed using uni- and multivariate methods. Participating countries were asked to provide baseline samples and not target potential hotspots. Chemometric analysis was possible for only three of the 15 PFAS monitored, namely perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS). The assessments showed that PFAS contamination in developing countries and in all matrices considered was almost equally attributed to PFOS and PFOA; PFHxS did not play a role. Subsequently, across all samples, PFOS and PFOA were strongly negatively correlated (spearman correlation coefficient r = −0.94). The measured values showed moderate positive correlation between PFOS and PFOA (r = 0.76) indicating common sources or environmental behavior. No clear pattern could be observed for geographic locations nor for transfers between matrices. Whereas the abiotic samples—soil, sediment, air—gave a very heterogenous picture (very small p-values) and had wide ranges and outliers, the measured values of the biota samples were not significantly different between matrices.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43231776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-10DOI: 10.3389/frans.2022.1014017
Yushu Gu, Miaomiao Liu, R. Quinn
Understanding molecular level interactions between the metabolome and proteome, two of the most important classes of molecules in biology, will generate deeper insight into the function of metabolites (natural products) which have a central role in interactions with therapeutic targets. Drug discovery in today’s pharmaceutical environment is driven by high-throughput screening of large chemical libraries. It is now 10 years since we published a paper on the development of natural product fraction libraries with control of LogP properties. We have now turned our attention to using pure natural product libraries to address the timeframe issues associated with isolation and characterization of the active constituent(s). Native mass spectrometry can be used as a robust platform for identifying the interactions between natural products and their protein targets. The recent development of Collision-Induced Affinity Selection mass spectrometry, a technique using capture of ligand-protein complexes followed by collision induced dissociation to identify library hits followed by direct ligand-protein confirmation in native mass spectrometry also enables screening of a greater proportion of human proteins. We will review native mass spectrometry-based approaches to use natural product extracts, pre-fractionated natural product libraries and pure natural product libraries for screening against molecular targets. We will also discuss some of the other mass-spectrometry based applications that have been implicated in natural product drug discovery.
{"title":"Metabolite-protein interactions: Native mass spectrometry and collision induced affinity selection mass spectrometry in natural product screening","authors":"Yushu Gu, Miaomiao Liu, R. Quinn","doi":"10.3389/frans.2022.1014017","DOIUrl":"https://doi.org/10.3389/frans.2022.1014017","url":null,"abstract":"Understanding molecular level interactions between the metabolome and proteome, two of the most important classes of molecules in biology, will generate deeper insight into the function of metabolites (natural products) which have a central role in interactions with therapeutic targets. Drug discovery in today’s pharmaceutical environment is driven by high-throughput screening of large chemical libraries. It is now 10 years since we published a paper on the development of natural product fraction libraries with control of LogP properties. We have now turned our attention to using pure natural product libraries to address the timeframe issues associated with isolation and characterization of the active constituent(s). Native mass spectrometry can be used as a robust platform for identifying the interactions between natural products and their protein targets. The recent development of Collision-Induced Affinity Selection mass spectrometry, a technique using capture of ligand-protein complexes followed by collision induced dissociation to identify library hits followed by direct ligand-protein confirmation in native mass spectrometry also enables screening of a greater proportion of human proteins. We will review native mass spectrometry-based approaches to use natural product extracts, pre-fractionated natural product libraries and pure natural product libraries for screening against molecular targets. We will also discuss some of the other mass-spectrometry based applications that have been implicated in natural product drug discovery.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44210636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-10DOI: 10.3389/frans.2022.1018080
L. Tinoco, Bruno da Silva Santos, Jhones Matheus da Silva Soares, Fernanda G. Finelli
Ornithine decarboxylase (ODC) catalyzes the decarboxylation of ornithine to produce putrescine, the first step in the metabolism of polyamines (putrescine, spermidine, and spermine), which are essential growth factors in eukaryotic cells. ODC is active as a homodimer and depends on pyridoxal 5′-phosphate (PLP) as a cofactor. An increase in the concentration of polyamines has been associated with carcinogenesis. Therefore, there is much interest in identifying inhibitors of this pathway as potential chemotherapeutic and chemopreventive agents. The best-known inhibitor of mammalian ODC is α-difluoromethylornithine (DFMO), a highly selective compound that alkylates Cys-360 (a residue of the ODC active site). Although DFMO was initially developed for the treatment of cancer, the World Health Organization recommends its use in combination with nifurtimox for the treatment of human African trypanosomiasis. Considering the importance of ODC as a promising target for the treatment of various types of cancer and other infectious diseases, choosing the right method for screening potential inhibitors can help to accelerate the discovery of new drugs. Several methods for the determination of ODC activity are found in the literature. Among these, we can mention analysis with radioactive markers, colorimetric assays using auxiliary enzymes to detect CO2 or H2O2 release, chromatographic separations with putrescine derivatization, mass spectrometry, and spectroscopic techniques. In this review, the main analysis methods used will be described, highlighting their advantages and disadvantages, as well as identifying the most promising methods for high-throughput screening.
{"title":"Analytical assays to evaluate enzymatic activity and screening of inhibitors for ornithine decarboxylase","authors":"L. Tinoco, Bruno da Silva Santos, Jhones Matheus da Silva Soares, Fernanda G. Finelli","doi":"10.3389/frans.2022.1018080","DOIUrl":"https://doi.org/10.3389/frans.2022.1018080","url":null,"abstract":"Ornithine decarboxylase (ODC) catalyzes the decarboxylation of ornithine to produce putrescine, the first step in the metabolism of polyamines (putrescine, spermidine, and spermine), which are essential growth factors in eukaryotic cells. ODC is active as a homodimer and depends on pyridoxal 5′-phosphate (PLP) as a cofactor. An increase in the concentration of polyamines has been associated with carcinogenesis. Therefore, there is much interest in identifying inhibitors of this pathway as potential chemotherapeutic and chemopreventive agents. The best-known inhibitor of mammalian ODC is α-difluoromethylornithine (DFMO), a highly selective compound that alkylates Cys-360 (a residue of the ODC active site). Although DFMO was initially developed for the treatment of cancer, the World Health Organization recommends its use in combination with nifurtimox for the treatment of human African trypanosomiasis. Considering the importance of ODC as a promising target for the treatment of various types of cancer and other infectious diseases, choosing the right method for screening potential inhibitors can help to accelerate the discovery of new drugs. Several methods for the determination of ODC activity are found in the literature. Among these, we can mention analysis with radioactive markers, colorimetric assays using auxiliary enzymes to detect CO2 or H2O2 release, chromatographic separations with putrescine derivatization, mass spectrometry, and spectroscopic techniques. In this review, the main analysis methods used will be described, highlighting their advantages and disadvantages, as well as identifying the most promising methods for high-throughput screening.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43666351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-30DOI: 10.3389/frans.2022.1012707
Mowei Zhou, J. Fulcher, Kevin J. Zemaitis, David J. Degnan, Yen-Chen Liao, Marija Veličković, D. Veličković, L. Bramer, William R. Kew, G. Stacey, L. Paša-Tolić
Proteomic methods have been widely used to study proteins in complex biological samples to understand biological molecular mechanisms. Most well-established methods (known as bottom-up proteomics, BUP) employ an enzymatic digestion step to cleave intact proteins into smaller peptides for liquid chromatography (LC) mass spectrometry (MS) detection. In contrast, top-down proteomics (TDP) directly characterizes intact proteins including all possible post-translational modifications (PTMs), thus offering unique insights into proteoform biology where combinations of individual PTMs may play important roles. We performed TDP on soybean root nodules infected by the symbiotic Bradyrhizobium japonicum in both the wildtype bacterium and a nifH- mutant, which lacks the ability to fix nitrogen in the soybean root nodule. TDP captured 1648 proteoforms derived from 313 bacterial genes and 178 soybean genes. Leghemoglobin, the most abundant protein in the sample, existed in many truncated proteoforms. Interestingly, these truncated proteoforms were considerably more abundant in the wildtype relative to the nifH- mutant, implicating protease activity as an important factor in nitrogen fixation. Proteoforms with various PTMs and combinations thereof were identified using an unrestricted open modification search. This included less common PTMs such as myristoylation, palmitoylation, cyanylation, and sulfation. In parallel, we collected high resolution MS imaging (MSI) data of intact proteins and biopolymers (<20 kDa due to current technical limitations) from sections of the soybean root nodules using matrix-assisted laser desorption/ionization (MALDI) coupled to high resolution Orbitrap. Several detected proteoforms exhibited unique spatial distributions inside the infection zone and cortex, suggesting functional compartmentalization in these regions. A subset of peaks from the MALDI-MSI were assigned to proteoforms detected in TDP LCMS data based on matching accurate masses. Many of the proteins detected in both LCMS and MALDI-MSI are currently uncharacterized in UniProt: the PTM and spatial information presented here will be valuable in understanding their biological functions. Taken together, our study demonstrates how untargeted TDP approach can provide unique insights into plant proteoform biology. On-going technology developments are expected to further improve TDP coverage for more comprehensive high-throughput analysis of proteoforms.
{"title":"Discovery top-down proteomics in symbiotic soybean root nodules","authors":"Mowei Zhou, J. Fulcher, Kevin J. Zemaitis, David J. Degnan, Yen-Chen Liao, Marija Veličković, D. Veličković, L. Bramer, William R. Kew, G. Stacey, L. Paša-Tolić","doi":"10.3389/frans.2022.1012707","DOIUrl":"https://doi.org/10.3389/frans.2022.1012707","url":null,"abstract":"Proteomic methods have been widely used to study proteins in complex biological samples to understand biological molecular mechanisms. Most well-established methods (known as bottom-up proteomics, BUP) employ an enzymatic digestion step to cleave intact proteins into smaller peptides for liquid chromatography (LC) mass spectrometry (MS) detection. In contrast, top-down proteomics (TDP) directly characterizes intact proteins including all possible post-translational modifications (PTMs), thus offering unique insights into proteoform biology where combinations of individual PTMs may play important roles. We performed TDP on soybean root nodules infected by the symbiotic Bradyrhizobium japonicum in both the wildtype bacterium and a nifH- mutant, which lacks the ability to fix nitrogen in the soybean root nodule. TDP captured 1648 proteoforms derived from 313 bacterial genes and 178 soybean genes. Leghemoglobin, the most abundant protein in the sample, existed in many truncated proteoforms. Interestingly, these truncated proteoforms were considerably more abundant in the wildtype relative to the nifH- mutant, implicating protease activity as an important factor in nitrogen fixation. Proteoforms with various PTMs and combinations thereof were identified using an unrestricted open modification search. This included less common PTMs such as myristoylation, palmitoylation, cyanylation, and sulfation. In parallel, we collected high resolution MS imaging (MSI) data of intact proteins and biopolymers (<20 kDa due to current technical limitations) from sections of the soybean root nodules using matrix-assisted laser desorption/ionization (MALDI) coupled to high resolution Orbitrap. Several detected proteoforms exhibited unique spatial distributions inside the infection zone and cortex, suggesting functional compartmentalization in these regions. A subset of peaks from the MALDI-MSI were assigned to proteoforms detected in TDP LCMS data based on matching accurate masses. Many of the proteins detected in both LCMS and MALDI-MSI are currently uncharacterized in UniProt: the PTM and spatial information presented here will be valuable in understanding their biological functions. Taken together, our study demonstrates how untargeted TDP approach can provide unique insights into plant proteoform biology. On-going technology developments are expected to further improve TDP coverage for more comprehensive high-throughput analysis of proteoforms.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49384069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-12DOI: 10.3389/frans.2022.941883
J. C. Barreiro, A. P. Florentino, I. L. Furlani, Gustavo H. R. Silva, Q. Cass
An analytical method was developed to quantify a mixture of acetaminophen, metoprolol, methylparaben, carbamazepine, naproxen, estrone, estradiol, diclofenac, benzophenone, ibuprofen, progesterone, and mefenamic acid from domestic wastewater samples. To match fast and efficient chromatographic separation for different classes of compounds, an automated scouting liquid chromatographic system was associated with the experimental design produced by the DryLab® software. HLB cartridges were used to extract the analytes from the sample matrix, which was followed by detection and quantitation by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lowest detection limits were found for acetaminophen and carbamazepine (0.625 pg L−1) and metoprolol (0.4 pg L−1).
{"title":"An LC-MS/MS method for quantitation of methylparaben, benzophenone, and pharmaceutical compounds from domestic wastewater","authors":"J. C. Barreiro, A. P. Florentino, I. L. Furlani, Gustavo H. R. Silva, Q. Cass","doi":"10.3389/frans.2022.941883","DOIUrl":"https://doi.org/10.3389/frans.2022.941883","url":null,"abstract":"An analytical method was developed to quantify a mixture of acetaminophen, metoprolol, methylparaben, carbamazepine, naproxen, estrone, estradiol, diclofenac, benzophenone, ibuprofen, progesterone, and mefenamic acid from domestic wastewater samples. To match fast and efficient chromatographic separation for different classes of compounds, an automated scouting liquid chromatographic system was associated with the experimental design produced by the DryLab® software. HLB cartridges were used to extract the analytes from the sample matrix, which was followed by detection and quantitation by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lowest detection limits were found for acetaminophen and carbamazepine (0.625 pg L−1) and metoprolol (0.4 pg L−1).","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46485196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-12DOI: 10.3389/frans.2022.971352
Alejandro J. Mancilla-Rico, Eduardo Rodríguez de San Miguel
Polymer inclusion membranes (PIMs) are developed to be used as colorimetric sensors for the simultaneous determination and quantification of Cu(II), Zn(II), Pb(II) from aqueous solutions using chemometric methods. Different physical and chemical factors that influence the detection process of the analytes are studied, i.e., the concentration of the metal cation, the amount of membrane, and the pH of the solution. The most significant variables within the detection process in membrane sensors are those that are closely related to the chemical reaction of the detection, that is, the concentration of the metal cation and the number of active sites available in the optomembrane. The reversibility and durability of the signal are evaluated as well. The optomembrane reaches 95% of the optical signal attributed to the process of formation of the different colorful complexes in 20 min, regardless of the metal cation. The optomembrane of CTA—TEHP—PAN presents a very narrow linear interval of response to the concentration of the cations, Zn(II) and Cu(II) ranging from 0.6 to 6 ppm; for higher concentrations the polymeric detector presents saturation. The response of the sensor to different concentrations of Pb(II) is not linear, which can be attributed to the lack of chemical affinity to generate the complex in the polymer film. The simultaneous determination of the three metal cations by three chemometric methods [multivariate curve resolution (MCR), artificial neural networks (ANNs) and partial least squares (PLS)] is performed with an experimental central composite design matrix at five levels and three experimental factors. The construction of the quantification model is carried out from the information obtained from the VIS spectrum of the PIMs exposed to the aqueous solutions. The predictive power of the quantification models for each of the metal cations is evaluated contemplating the determination coefficient (R2) and the root mean square error (RMSE) values. Results favors the use of the PLS algorithm, although due to the competition for the actives sites of the chromophore, Pb(II) determination is not satisfactorily acomplished. Principal component analysis (PCA) is in addition employed to visualize patterns in the synthesized membranes.
{"title":"Simultaneous determination of Cu(II), Zn(II), and Pb(II) from aqueous solutions using a polymer inclusion membrane (PIM) based-sensor with 1-(2-pyridylazo)-2-naphthol (PAN) as chromophore and chemometric methods","authors":"Alejandro J. Mancilla-Rico, Eduardo Rodríguez de San Miguel","doi":"10.3389/frans.2022.971352","DOIUrl":"https://doi.org/10.3389/frans.2022.971352","url":null,"abstract":"Polymer inclusion membranes (PIMs) are developed to be used as colorimetric sensors for the simultaneous determination and quantification of Cu(II), Zn(II), Pb(II) from aqueous solutions using chemometric methods. Different physical and chemical factors that influence the detection process of the analytes are studied, i.e., the concentration of the metal cation, the amount of membrane, and the pH of the solution. The most significant variables within the detection process in membrane sensors are those that are closely related to the chemical reaction of the detection, that is, the concentration of the metal cation and the number of active sites available in the optomembrane. The reversibility and durability of the signal are evaluated as well. The optomembrane reaches 95% of the optical signal attributed to the process of formation of the different colorful complexes in 20 min, regardless of the metal cation. The optomembrane of CTA—TEHP—PAN presents a very narrow linear interval of response to the concentration of the cations, Zn(II) and Cu(II) ranging from 0.6 to 6 ppm; for higher concentrations the polymeric detector presents saturation. The response of the sensor to different concentrations of Pb(II) is not linear, which can be attributed to the lack of chemical affinity to generate the complex in the polymer film. The simultaneous determination of the three metal cations by three chemometric methods [multivariate curve resolution (MCR), artificial neural networks (ANNs) and partial least squares (PLS)] is performed with an experimental central composite design matrix at five levels and three experimental factors. The construction of the quantification model is carried out from the information obtained from the VIS spectrum of the PIMs exposed to the aqueous solutions. The predictive power of the quantification models for each of the metal cations is evaluated contemplating the determination coefficient (R2) and the root mean square error (RMSE) values. Results favors the use of the PLS algorithm, although due to the competition for the actives sites of the chromophore, Pb(II) determination is not satisfactorily acomplished. Principal component analysis (PCA) is in addition employed to visualize patterns in the synthesized membranes.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48323880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-12DOI: 10.3389/frans.2022.1002935
Sam Wouters, Ils Pijpers, Ninon Vanden Haute, Daniel Meston, L. Dillen, F. Cuyckens, S. Eeltink
This study reports on the potential of using ion-exchange suppressor technology in liquid chromatography—electrospray ionization mass spectrometry workflows. The aim was to use high salt concentrations to improve separation performance, while overcoming the resulting significant ion suppression during electrospray ionization. As a case study, we apply suppressor technology to the hydrophilic interaction liquid chromatography separation and detection of taurine and glycochenodeoxycholate sulfate, endogenous biomarkers for organic anion transporter protein inhibition. The desired chromatographic selectivity was achieved applying 100 mM ion-pairing agent, while competing ions negatively affecting MS sensitivity were actively removed post-column from the solvent via a charged partially permeable membrane and replaced with protons, resulting in an up to 10-fold increase in detection sensitivity.
{"title":"Making high salt concentrations for optimal chromatography compatible with electrospray ionization mass spectrometry using an ion exchange membrane suppressor: Analysis of biomarkers for transporter protein inhibition as a case study","authors":"Sam Wouters, Ils Pijpers, Ninon Vanden Haute, Daniel Meston, L. Dillen, F. Cuyckens, S. Eeltink","doi":"10.3389/frans.2022.1002935","DOIUrl":"https://doi.org/10.3389/frans.2022.1002935","url":null,"abstract":"This study reports on the potential of using ion-exchange suppressor technology in liquid chromatography—electrospray ionization mass spectrometry workflows. The aim was to use high salt concentrations to improve separation performance, while overcoming the resulting significant ion suppression during electrospray ionization. As a case study, we apply suppressor technology to the hydrophilic interaction liquid chromatography separation and detection of taurine and glycochenodeoxycholate sulfate, endogenous biomarkers for organic anion transporter protein inhibition. The desired chromatographic selectivity was achieved applying 100 mM ion-pairing agent, while competing ions negatively affecting MS sensitivity were actively removed post-column from the solvent via a charged partially permeable membrane and replaced with protons, resulting in an up to 10-fold increase in detection sensitivity.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41327837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-07DOI: 10.3389/frans.2022.1004113
Pamella Christina Ortega de Oliveira, Renato C. S. Lessa, M. S. Ceroullo, C. A. Wegermann, M. D. de Moraes
Enzymes are targets commonly explored in screening assays aiming to discover new leads in the drug development process. Among the diverse assay models to identify new enzymatic inhibitors, on-flow assays based on liquid chromatography (LC) can be highlighted. In these approaches, the ligand-enzyme interaction can be examined by monitoring the catalytic activity or the affinity/retention. Most applications use the biological target immobilized in solid supports resulting in the acquisition of an immobilized enzymatic reactor (IMER). Coupling IMERs to LC or mass spectrometry (MS) systems allows monitoring enzyme activity online and studying binding events between target and ligands. On-flow screening assays present many advantages for the hit-to-lead process, such as the possibility of system automation, reusability, and high stability. This review covers articles from the last decade that combine the use of varied immobilization methods on different solid supports and several equipment setups in on-flow systems, emphasizing the performance and capacity of recognizing and identifying biologically active compounds in various matrices.
{"title":"On-flow enzymatic inhibitor screening: The emerging success of liquid chromatography-based assays","authors":"Pamella Christina Ortega de Oliveira, Renato C. S. Lessa, M. S. Ceroullo, C. A. Wegermann, M. D. de Moraes","doi":"10.3389/frans.2022.1004113","DOIUrl":"https://doi.org/10.3389/frans.2022.1004113","url":null,"abstract":"Enzymes are targets commonly explored in screening assays aiming to discover new leads in the drug development process. Among the diverse assay models to identify new enzymatic inhibitors, on-flow assays based on liquid chromatography (LC) can be highlighted. In these approaches, the ligand-enzyme interaction can be examined by monitoring the catalytic activity or the affinity/retention. Most applications use the biological target immobilized in solid supports resulting in the acquisition of an immobilized enzymatic reactor (IMER). Coupling IMERs to LC or mass spectrometry (MS) systems allows monitoring enzyme activity online and studying binding events between target and ligands. On-flow screening assays present many advantages for the hit-to-lead process, such as the possibility of system automation, reusability, and high stability. This review covers articles from the last decade that combine the use of varied immobilization methods on different solid supports and several equipment setups in on-flow systems, emphasizing the performance and capacity of recognizing and identifying biologically active compounds in various matrices.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43783823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-05DOI: 10.3389/frans.2022.994394
Zhixue Zhou, Jimmy Gu, J. Brennan, Yingfu Li
We report on the design of a simple all-DNA circuit with dual functions of signal amplification and signal reporting and its use for detection of human telomerase activity from cancer cells. The system utilizes a catalytic hairpin assembly (CHA) reaction for amplification, which produces split G-quadruplex outputs that assemble to form complete guanine quadruplex structures as reporting modules. As designed, a linear DNA sequence (the target) functions as a catalyst to drive cyclic programmed assembly of two hairpins, producing a DNA duplex with two guanine-rich sequences that assemble to form a complete Gq structure. The formation of the Gq element allows either fluorescence or colorimetric detection of the target. Examples are provided to demonstrate fluorescence detection of cancer cells’ telomerase activities in solution and the first example of a CHA-modulated colorimetric assay for detecting telomerase activities of cancer cells using a simple paper device.
{"title":"An all-deoxyribonucleic acid circuit for detection of human telomerase activity in solution and on paper","authors":"Zhixue Zhou, Jimmy Gu, J. Brennan, Yingfu Li","doi":"10.3389/frans.2022.994394","DOIUrl":"https://doi.org/10.3389/frans.2022.994394","url":null,"abstract":"We report on the design of a simple all-DNA circuit with dual functions of signal amplification and signal reporting and its use for detection of human telomerase activity from cancer cells. The system utilizes a catalytic hairpin assembly (CHA) reaction for amplification, which produces split G-quadruplex outputs that assemble to form complete guanine quadruplex structures as reporting modules. As designed, a linear DNA sequence (the target) functions as a catalyst to drive cyclic programmed assembly of two hairpins, producing a DNA duplex with two guanine-rich sequences that assemble to form a complete Gq structure. The formation of the Gq element allows either fluorescence or colorimetric detection of the target. Examples are provided to demonstrate fluorescence detection of cancer cells’ telomerase activities in solution and the first example of a CHA-modulated colorimetric assay for detecting telomerase activities of cancer cells using a simple paper device.","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48485606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-30DOI: 10.3389/frans.2022.932857
Clément Martin, Noémie Willem, Sorenza Desablens, Vincent Menard, Sophia Tajri, S. Blanchard, Y. Brostaux, F. Verheggen, C. Diederich
Dogs have a powerful olfactory system, which is used in many areas of the police and military to detect drugs, human remains, and explosives, among other items. Despite these powerful detection abilities, methods assessing the performance (MAP) of dogs remain scarce, and have never been validated. In particular, scientific knowledge on post-training performance assessments is scarce. To validate a quantitative MAP, an efficient detection dog (DD) must first be defined. Here, we aimed to define what an efficient DD is, and to develop a quantitative MAP. Specifically, we conducted 1) an international survey sent to professional DD practitioners (n = 50), and 2) an experimental assay on cadaver and drug DDs (n = 20). Based on the survey, efficient DDs were defined as confident animals, making few mistakes, alerting to the presence of target odors as close as possible, able to strategically screen the search area effectively, independent and not easily distracted. The developed quantitative MAP was based on video tracking DDs in a circular behavioral arena, in which the error rate of DD was recorded, including accuracy and the strategy level. Previous studies have already demonstrated that DDs are usually confidant. Guidance was not assessed during MAP development; however, handlers could not guide DDs during the search session. Based on this method, future studies should evaluate DD performance throughout the entire training process. Such monitoring would allow thresholds to be determined, allowing efficient DDs to be identified, along with the effect of certain factors on performance (e.g., dogs breed, gender, and training aids used during DD conditioning).
{"title":"What a good boy! Deciphering the efficiency of detection dogs","authors":"Clément Martin, Noémie Willem, Sorenza Desablens, Vincent Menard, Sophia Tajri, S. Blanchard, Y. Brostaux, F. Verheggen, C. Diederich","doi":"10.3389/frans.2022.932857","DOIUrl":"https://doi.org/10.3389/frans.2022.932857","url":null,"abstract":"Dogs have a powerful olfactory system, which is used in many areas of the police and military to detect drugs, human remains, and explosives, among other items. Despite these powerful detection abilities, methods assessing the performance (MAP) of dogs remain scarce, and have never been validated. In particular, scientific knowledge on post-training performance assessments is scarce. To validate a quantitative MAP, an efficient detection dog (DD) must first be defined. Here, we aimed to define what an efficient DD is, and to develop a quantitative MAP. Specifically, we conducted 1) an international survey sent to professional DD practitioners (n = 50), and 2) an experimental assay on cadaver and drug DDs (n = 20). Based on the survey, efficient DDs were defined as confident animals, making few mistakes, alerting to the presence of target odors as close as possible, able to strategically screen the search area effectively, independent and not easily distracted. The developed quantitative MAP was based on video tracking DDs in a circular behavioral arena, in which the error rate of DD was recorded, including accuracy and the strategy level. Previous studies have already demonstrated that DDs are usually confidant. Guidance was not assessed during MAP development; however, handlers could not guide DDs during the search session. Based on this method, future studies should evaluate DD performance throughout the entire training process. Such monitoring would allow thresholds to be determined, allowing efficient DDs to be identified, along with the effect of certain factors on performance (e.g., dogs breed, gender, and training aids used during DD conditioning).","PeriodicalId":73063,"journal":{"name":"Frontiers in analytical science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47553238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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