In this study, we established a comprehensive method for simultaneous identification and quantification of tetrodotoxin （TTX） in fresh pufferfish tissues and pufferfish-based products using liquid chromatography/qua...In this study, we established a comprehensive method for simultaneous identification and quantification of tetrodotoxin （TTX） in fresh pufferfish tissues and pufferfish-based products using liquid chromatography/quadrupole-linear ion trap mass spectrometry （LC-QqLIT-MS）. TTX was extracted by 1% acetic acid-methanol, and most of the lipids were then removed by freezing lipid precipitation, followed by purification and concentration using immunoaffinity columns （IACs）. Matrix effects were substantially reduced due to the high specificity of the IACs, and thus, background interference was avoided. Quantitation analysis was therefore performed using an external calibration curve with standards prepared in mobile phase. The method was evaluated by fortifying samples at 1, 10, and 100 ng/g, respectively, and the recoveries ranged from 75.8%--107%, with a relative standard deviation of less than 15%. The TTX calibration curves were linear over the range of 1-1 000 ~tg/L, with a detection limit of 0.3 ng/g and a quantification limit of 1 ng/g. Using this method, samples can be further analyzed using an information- dependent acquisition （IDA） experiment, in the positive mode, from a single liquid chromatography-tandem mass spectrometry injection, which can provide an extra level of confirmation by matching the full product ion spectra acquired for a standard sample with those from an enhanced product ion （EPI） library. The scheduled multiple reaction monitoring method enabled TTX to be screened for, and TTX was positively identified using the IDA and EPI spectra. This method was successfully applied to analyze a total of 206 samples of fresh pufferfish tissues and pufferfish-based products. The results from this study show that the proposed method can be used to quantify and identify TTX in a single run with excellent sensitivity and reproducibility, and is suitable for the analysis of complex matrix pufferfish samples.展开更多
A rapid, simple and accurate method using an immunoaffinity column (IAC) and capillary electrophoresis (CE) for the analysis of the major alkaloids in opium is developed. The IAC was synthesized by coupling specific m...A rapid, simple and accurate method using an immunoaffinity column (IAC) and capillary electrophoresis (CE) for the analysis of the major alkaloids in opium is developed. The IAC was synthesized by coupling specific morphine polyclonal antibodies to CNBr-actived Sepharose 4B. The IAC showed high selectivity and obvious enrichment to morphine, codeine, dionin and thebaine. The extraction solution was analyzed by CE with β-cyclodextrin as an additive. Recoveries of the four alkaloids from PBS were between 93%-105% with RSD value less than 5.0%. The result showed that this method was practical for the determination of morphine analogs in opium.展开更多
We describe a two-step method that uses wheat germ agglutinin immobilized on Sepharose gel followed by immunoaffinity chromatography (IAC) to extract recombinant human erythropoietin and Darbepoetin from equine plasma...We describe a two-step method that uses wheat germ agglutinin immobilized on Sepharose gel followed by immunoaffinity chromatography (IAC) to extract recombinant human erythropoietin and Darbepoetin from equine plasma. Lectin affinity chromatography was shown to be an effective approach for isolating these epoetins from plasma and in combination with IAC;this method gave superior recovery when compared to the use of the latter technique alone. Moreover, due to the ease with which it can be scaled up, it is particularly well suited for pre-concentrating larger volumes of samples prior to IAC and this provides a facile way of improving the overall sensitivity with which these foreign proteins can be detected in equine plasma.展开更多
The lack of selective extraction specific for lysine-acetylated proteins has been a major problem in the field of acetylation biology,though acetylation plays a key role in many biological processes.In this paper,we r...The lack of selective extraction specific for lysine-acetylated proteins has been a major problem in the field of acetylation biology,though acetylation plays a key role in many biological processes.In this paper,we report for the first time the proteomic screening of lysine-acetylated proteins from a mouse liver tissue,by a new approach of immunoaffinity purification of lysine-acetylated peptides combined with nano-HPLC/MS/MS analysis.We have found 20 lysine-acetylated proteins with 21 lysine-acetylated sites,among which 12 lysine-acetylated proteins and 16 lysine-acetylated sites have never been reported before.Notably,three acetyltransferases harboring in mitochondrion are newly discovered acetyltransferases responsible for the acetylation of nonhistone proteins.We have explored the significant patterns of residue preference by the hierarchical clustering analysis of amino acid residues surrounding acetylation sites,which could be helpful to the prediction of new sites of lysine acetylation.Our findings provide more candidates for studying the important roles played by acetylation in diverse cellular pathways and related human diseases.展开更多
An immunochemical sol-gel-based immunoaffinity purification (IAP) method for purification and detection of the progestin drug medroxyprogesterone acetate (MPA) was developed. A polyclonal antibody (Ab) for MPA was gen...An immunochemical sol-gel-based immunoaffinity purification (IAP) method for purification and detection of the progestin drug medroxyprogesterone acetate (MPA) was developed. A polyclonal antibody (Ab) for MPA was generated, and two competitive (indirect and direct) sensitive enzyme-linked immunosorbent assays (ELISAs) for its detection were developed and implemented to determine the recovery and efficiency of the sol-gel based IAP method. The detection limits of the assays were 1.4 ± 0.2 ng·mL-1 (n = 4) and 4.0 ± 0.4 ng·mL-1 (n = 25) for the indirect and direct ELISAs, respectively. The Abs did not exhibit cross-reactivity with any other progestin or steroid hormone, with the exception of megestrol acetate, with which the Ab exhibited 76% cross-reactivity. The sol-gel IAP method successfully eliminated serum interference to a degree that enabled ELISA analysis of spiked serum samples. This method was also found fully compatible with subsequent chemical analytical methods, such as liquid chromatography followed by mass spectrometry (LC-MS/MS). The approaches developed in this study form a basis for analysis of MPA in biological samples and may be further used to study population exposure to MPA and to monitor MPA contamination in water samples.展开更多
Photo-Electric Microbe Sensor is a patented biotechnology that detects microbes in aqueous solution by measuring the change in photo-voltage in response to UV light stimulation of a platinum (Pt) disk surface on an el...Photo-Electric Microbe Sensor is a patented biotechnology that detects microbes in aqueous solution by measuring the change in photo-voltage in response to UV light stimulation of a platinum (Pt) disk surface on an electrode before and after immunoprecipitation of microbes. This study aimed to increase the sensitivity of microbe detection by pre-adsorbing recombinant Streptococcal Protein G (PG), to the Pt sensor surface. Streptococcal PG binds the Fc region of mammalian IgG molecules and we investigated the association of PG to Pt and the resulting ability to tether antibodies to the Pt-PG surface. An ELISA protocol was optimized to detect the presence of mouse monoclonal antibodies tethered to Pt immunoaffinity disks, and to determine the recommended blocking solution and reagent concentrations. Our results demonstrate that PG binds to bare Pt, increases IgG affinity to the Pt surface following Superblock Buffer application, and together offers design-options for Pt-based sensor technologies.展开更多
Aflatoxins are a group of highly carcinogenic mycotoxins that contaminate a wide variety of agricultural crops and have a detrimental economic impact on industries, such as corn and ethanol production. They are regula...Aflatoxins are a group of highly carcinogenic mycotoxins that contaminate a wide variety of agricultural crops and have a detrimental economic impact on industries, such as corn and ethanol production. They are regulated by the FDA, and therefore, rapid, reliable cleanup techniques with low detection limits are needed for aflatoxins in a wide array of matrices. In this study the effect of using an immunoaffinity column versus simple filtering as a cleanup was tested for afltoxins extracted from corn and Dried Distillers Grains (DDG). The aflatoxins were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The use of an immunoaffinity column resulted in greater signal-to-noise ratios (S/N), S/N of 70 vs. S/N of 5 for corn, as well as fewer non-target peaks in the analysis. Recoveries of aflatoxin using immunoaffinity ranged from 40% to 104.5% (spiked substrate) and 49% to 120% (spiked extract) while percent recoveries of filtered samples ranged from 84% to 119% (spiked substrate) and 88% to 119% (spiked extract). This comparison study showed that filtering is acceptable for small sample sets or where rapid throughput is needed. However, for larger sample sets a more stringent cleanup method is necessary to ensure instrument performance.展开更多
Monoclonal antibodies(MAbs) against natural products with low-molecular weights have become an important tool when combined with other analytical systems. Eastern blotting involves a typical staining system wherein, f...Monoclonal antibodies(MAbs) against natural products with low-molecular weights have become an important tool when combined with other analytical systems. Eastern blotting involves a typical staining system wherein, for example, glycosides can be blotted to a membrane and cross-linked and stained using MAbs. An immunoaffinity column combined with a monoclonal antibody allows a one-step purification of hapten compounds or preparation of a knockout extract that removes only the target hapten molecules from a crude extract. Here, we discuss the application of these extracts. Single-chain variable fragment(scFv) proteins have led to novel assay systems such as fluobodies or antibodies coupled with green fluorescent protein for natural products. A typical novel application of a scFv gene would be in the context of plant breeding; this is designated "missile-type" molecular breeding, intended to increase hapten molecule concentrations in transgenic plants.展开更多
基金Supported by the National Natural Science Foundation of China(No.41106109)the China National Food Safety Standards Development Project(No.ZHENGHE-2015-356)
文摘In this study, we established a comprehensive method for simultaneous identification and quantification of tetrodotoxin （TTX） in fresh pufferfish tissues and pufferfish-based products using liquid chromatography/quadrupole-linear ion trap mass spectrometry （LC-QqLIT-MS）. TTX was extracted by 1% acetic acid-methanol, and most of the lipids were then removed by freezing lipid precipitation, followed by purification and concentration using immunoaffinity columns （IACs）. Matrix effects were substantially reduced due to the high specificity of the IACs, and thus, background interference was avoided. Quantitation analysis was therefore performed using an external calibration curve with standards prepared in mobile phase. The method was evaluated by fortifying samples at 1, 10, and 100 ng/g, respectively, and the recoveries ranged from 75.8%--107%, with a relative standard deviation of less than 15%. The TTX calibration curves were linear over the range of 1-1 000 ~tg/L, with a detection limit of 0.3 ng/g and a quantification limit of 1 ng/g. Using this method, samples can be further analyzed using an information- dependent acquisition （IDA） experiment, in the positive mode, from a single liquid chromatography-tandem mass spectrometry injection, which can provide an extra level of confirmation by matching the full product ion spectra acquired for a standard sample with those from an enhanced product ion （EPI） library. The scheduled multiple reaction monitoring method enabled TTX to be screened for, and TTX was positively identified using the IDA and EPI spectra. This method was successfully applied to analyze a total of 206 samples of fresh pufferfish tissues and pufferfish-based products. The results from this study show that the proposed method can be used to quantify and identify TTX in a single run with excellent sensitivity and reproducibility, and is suitable for the analysis of complex matrix pufferfish samples.
文摘A rapid, simple and accurate method using an immunoaffinity column (IAC) and capillary electrophoresis (CE) for the analysis of the major alkaloids in opium is developed. The IAC was synthesized by coupling specific morphine polyclonal antibodies to CNBr-actived Sepharose 4B. The IAC showed high selectivity and obvious enrichment to morphine, codeine, dionin and thebaine. The extraction solution was analyzed by CE with β-cyclodextrin as an additive. Recoveries of the four alkaloids from PBS were between 93%-105% with RSD value less than 5.0%. The result showed that this method was practical for the determination of morphine analogs in opium.
文摘We describe a two-step method that uses wheat germ agglutinin immobilized on Sepharose gel followed by immunoaffinity chromatography (IAC) to extract recombinant human erythropoietin and Darbepoetin from equine plasma. Lectin affinity chromatography was shown to be an effective approach for isolating these epoetins from plasma and in combination with IAC;this method gave superior recovery when compared to the use of the latter technique alone. Moreover, due to the ease with which it can be scaled up, it is particularly well suited for pre-concentrating larger volumes of samples prior to IAC and this provides a facile way of improving the overall sensitivity with which these foreign proteins can be detected in equine plasma.
基金support from the National Natural Science Foundation of China(Grant Nos.20675020&20735005)the National Science Foundation for Post-doctor of China(Grant No.20080440075)+2 种基金the Shanghai Leading Academic Discipline Project(Grant No.B109)the Shanghai Municipal Health Bureau(Grant No.2008Y024)the Shanghai Postdoctoral Sustentation Fund
文摘The lack of selective extraction specific for lysine-acetylated proteins has been a major problem in the field of acetylation biology,though acetylation plays a key role in many biological processes.In this paper,we report for the first time the proteomic screening of lysine-acetylated proteins from a mouse liver tissue,by a new approach of immunoaffinity purification of lysine-acetylated peptides combined with nano-HPLC/MS/MS analysis.We have found 20 lysine-acetylated proteins with 21 lysine-acetylated sites,among which 12 lysine-acetylated proteins and 16 lysine-acetylated sites have never been reported before.Notably,three acetyltransferases harboring in mitochondrion are newly discovered acetyltransferases responsible for the acetylation of nonhistone proteins.We have explored the significant patterns of residue preference by the hierarchical clustering analysis of amino acid residues surrounding acetylation sites,which could be helpful to the prediction of new sites of lysine acetylation.Our findings provide more candidates for studying the important roles played by acetylation in diverse cellular pathways and related human diseases.
文摘An immunochemical sol-gel-based immunoaffinity purification (IAP) method for purification and detection of the progestin drug medroxyprogesterone acetate (MPA) was developed. A polyclonal antibody (Ab) for MPA was generated, and two competitive (indirect and direct) sensitive enzyme-linked immunosorbent assays (ELISAs) for its detection were developed and implemented to determine the recovery and efficiency of the sol-gel based IAP method. The detection limits of the assays were 1.4 ± 0.2 ng·mL-1 (n = 4) and 4.0 ± 0.4 ng·mL-1 (n = 25) for the indirect and direct ELISAs, respectively. The Abs did not exhibit cross-reactivity with any other progestin or steroid hormone, with the exception of megestrol acetate, with which the Ab exhibited 76% cross-reactivity. The sol-gel IAP method successfully eliminated serum interference to a degree that enabled ELISA analysis of spiked serum samples. This method was also found fully compatible with subsequent chemical analytical methods, such as liquid chromatography followed by mass spectrometry (LC-MS/MS). The approaches developed in this study form a basis for analysis of MPA in biological samples and may be further used to study population exposure to MPA and to monitor MPA contamination in water samples.
文摘Photo-Electric Microbe Sensor is a patented biotechnology that detects microbes in aqueous solution by measuring the change in photo-voltage in response to UV light stimulation of a platinum (Pt) disk surface on an electrode before and after immunoprecipitation of microbes. This study aimed to increase the sensitivity of microbe detection by pre-adsorbing recombinant Streptococcal Protein G (PG), to the Pt sensor surface. Streptococcal PG binds the Fc region of mammalian IgG molecules and we investigated the association of PG to Pt and the resulting ability to tether antibodies to the Pt-PG surface. An ELISA protocol was optimized to detect the presence of mouse monoclonal antibodies tethered to Pt immunoaffinity disks, and to determine the recommended blocking solution and reagent concentrations. Our results demonstrate that PG binds to bare Pt, increases IgG affinity to the Pt surface following Superblock Buffer application, and together offers design-options for Pt-based sensor technologies.
文摘Aflatoxins are a group of highly carcinogenic mycotoxins that contaminate a wide variety of agricultural crops and have a detrimental economic impact on industries, such as corn and ethanol production. They are regulated by the FDA, and therefore, rapid, reliable cleanup techniques with low detection limits are needed for aflatoxins in a wide array of matrices. In this study the effect of using an immunoaffinity column versus simple filtering as a cleanup was tested for afltoxins extracted from corn and Dried Distillers Grains (DDG). The aflatoxins were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). The use of an immunoaffinity column resulted in greater signal-to-noise ratios (S/N), S/N of 70 vs. S/N of 5 for corn, as well as fewer non-target peaks in the analysis. Recoveries of aflatoxin using immunoaffinity ranged from 40% to 104.5% (spiked substrate) and 49% to 120% (spiked extract) while percent recoveries of filtered samples ranged from 84% to 119% (spiked substrate) and 88% to 119% (spiked extract). This comparison study showed that filtering is acceptable for small sample sets or where rapid throughput is needed. However, for larger sample sets a more stringent cleanup method is necessary to ensure instrument performance.
文摘Monoclonal antibodies(MAbs) against natural products with low-molecular weights have become an important tool when combined with other analytical systems. Eastern blotting involves a typical staining system wherein, for example, glycosides can be blotted to a membrane and cross-linked and stained using MAbs. An immunoaffinity column combined with a monoclonal antibody allows a one-step purification of hapten compounds or preparation of a knockout extract that removes only the target hapten molecules from a crude extract. Here, we discuss the application of these extracts. Single-chain variable fragment(scFv) proteins have led to novel assay systems such as fluobodies or antibodies coupled with green fluorescent protein for natural products. A typical novel application of a scFv gene would be in the context of plant breeding; this is designated "missile-type" molecular breeding, intended to increase hapten molecule concentrations in transgenic plants.
