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Incorporation of Heavy Water for rapid Detection of Salmonella typhimurium by Raman Microspectroscopy

FOOD ANALYTICAL METHODS 2018年第12期11卷 3551-3557页

作者： Feng, Jingjing Yao, Weirong Guo, Yahui Cheng, Yuliang Qian, He Xie, Yunfei Jiangnan Univ State Key Lab Food Sci & Technol Wuxi Peoples R China Jiangnan Univ Sch Food Sci & Technol Wuxi Peoples R China Jiangnan Univ Joint Int Res Lab Food Safety 1800 Lihu Ave Wuxi 214122 Jiangsu Peoples R China

The presence of foodborne pathogens is one of the leading causes of food safety incidents;hence, early monitoring of the status of microbial contamination is a permanent concern. Here, a rapid and sensitive method for detection of Salmonella typhimurium was firstly developed by combining heavy water (D2O) labeling and Raman microspectroscopy to measure bacterial metabolic activity. It was based on the characteristics of Raman signals of carbon-deuterium (C-D) vibration as cells incorporate deuterium in place of hydrogen (H) during biosynthetic activity, and the live and dead Salmonella typhimurium cells could be distinguished by their metabolic activity within 1h. The CD/(CD+CH)% of D2O-incorporated Salmonella typhimurium in logarithmic growth phase was linearly related to the log of the initial concentration, and Salmonella typhimurium with the initial concentration of 10(2)-10(6) colony-forming unit (CFU)/mL could be quantified within 4-8h. Furthermore, desirable recovery ranging from 95.41 to 106.6% was obtained to assess the practicality and stability of this method for rapid detection of Salmonella typhimurium in milk, indicating promising application for the detection of bacterial contamination in food.

关键词： Heavy water Raman microspectroscopy Salmonella typhimurium rapid quantification

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rapid qualitative and quantitative analyses of Asian ginseng in adulterated American ginseng preparations by UPLC/Q-TOF-MS

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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 2010年第1期52卷 66-72页

作者： Li, Li Luo, Guo-An Liang, Qiong-Lin Hu, Ping Wang, Yi-Ming Tsinghua Univ Dept Chem Key Lab Bioorgan Phosphorus Chem & Chem Biol Minist Educ Beijing 100084 Peoples R China E China Univ Sci & Technol Sch Pharm Shanghai 200237 Peoples R China E China Univ Sci & Technol Coll Chem & Mol Engn Shanghai 200237 Peoples R China

A new method using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was developed for the rapid qualitative and quantitative analyses of Asian ginseng (Panax ginseng ***) in adulterated American ginseng (Panax quinquefolium L) preparations within 2 min. The method was based on the baseline chromatographic separation of isomeric compounds of ginsenoside Rf and 24(R)-pseudoginsenoside F-11 two potential chemical markers present in Panax ginseng *** and P. quinquefolium L. methanolic extracts. The chromatographic separation was achieved by UPLC, which used a column with 1.7 mu m particle packing which enabled the higher peak capacity, greater resolution, increased sensitivity and higher speed of analysis. Ginsenoside Rf and 24(R)-pseudoginsenoside F-11 were separated on baseline with retention times of 1.5 and 1.7 min, respectively. Ginsenoside Rf and 24(R)-pseudoginsenoside F-11 were identified and conformed unambiguously by accurate mass measurement and their different fragmentation pathways were performed on Q-TOF-MS. Quantitative analysis was carried out under selective ion monitoring (SIM) mode. The limit of detection (LOD) of this UPLC/Q-TOF-MS analysis for ginsenoside Rf and 24(R)-pseudoginsenoside F-11 was 0.05 and 0.08 ng, respectively. Ginsenoside Rf was linear over the range of 0.164-16.4 ng with a correlation coefficient (R-2) of 0.9997, while 24(R)-pseudoginsenoside F-11 was linear from 0.243 to 24.3 ng with an R-2 of 0.9989. Furthermore, inter-day and intra-day precisions were obtained below 4.0% and the analytical method was fully validated. 12 batches of self-prepared adulterated samples, 11 batches of Asian ginseng, 16 batches of American ginseng and 13 batches of commercial American ginseng preparations were tested. The method developed is rapid, accurate, reliable and highly sensitive for qualitative and quantitative analyses of Asian ginseng and American ginseng. (C) 2009 Elsevier B.V. A

关键词： UPLC/Q-TOF-MS Ginsenoside Rf 24(R)-Pseudoginsenoside F-11 rapid quantification American ginseng preparation

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Evaluation of the information content in infrared spectra for protein secondary structure determination

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BIOPHYSICAL JOURNAL 2006年第8期90卷 2946-2957页

作者： Goormaghtigh, E Ruysschaert, JM Raussens, V Univ Libre Bruxelles Ctr Struct Biol & Bioinformat Lab Struct & Funct Biol Membranes Brussels Belgium

Fourier-transform infrared spectroscopy is a method of choice for the experimental determination of protein secondary structure. Numerous approaches have been developed during the past 15 years. A critical parameter that has not been taken into account systematically is the selection of the wavenumbers used for building the mathematical models used for structure prediction. The high quality of the current Fourier-transform infrared spectrometers makes the absorbance at every single wavenumber a valid and almost noiseless type of information. We address here the question of the amount of independent information present in the infrared spectra of proteins for the prediction of the different secondary structure contents. It appears that, at most, the absorbance at three distinct frequencies of the spectra contain all the nonredundant information that can be related to one secondary structure content. The ascending stepwise method proposed here identifies the relevance of each wavenumber of the infrared spectrum for the prediction of a given secondary structure and yields a particularly simple method for computing the secondary structure content. Using the 50-protein database built beforehand to contain as little fold redundancy as possible, the standard error of prediction in cross-validation is 5.5% for the alpha-helix, 6.6% for the beta- sheet, and 3.4% for the beta-turn.

关键词： HYDROGEN-DEUTERIUM EXCHANGE CIRCULAR-DICHROISM SPECTRA PARTIALLEAST-SQUARES FTIR SPECTROSCOPY MEMBRANE-PROTEINS AMIDE-I rapid quantification DOMAIN-STRUCTURES H2O SOLUTIONS SIDE-CHAINS

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rapid monitoring of Escherichia coli and Enterococcus spp. in bathing water using Reverse Transcription-quantitative PCR

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INTERNATIONAL JOURNAL OF HYGIENE AND ENVIRONMENTAL HEALTH 2011年第6期214卷 478-484页

作者： Bergeron, P. Oujati, H. Catalan Cuenca, V. Huguet Mestre, J. M. Courtois, S. Suez Environm CIRSEE F-78230 Le Pecq France Rivages Pro Tech F-64210 Bidart France Lonza Biosci SAS Biopole Clermont Limagne F-63360 St Beauzire France Labaqua Dracma Alicante 03114 Spain Aigues Barcelona Barcelona 08028 Spain

For accompanying actions to pollution crisis management of recreational waters, rapid methods providing a quantified faecal indicator which can be completed in less than half a day, are currently needed. Two sensitive rRNA-targeted Reverse Transcription-quantitative PCR (RT-qPCR) methods were developed for quantifying Escherichia coli and Enterococcus spp. cells in marine bathing waters. Threshold cycle (Ct) values were found to be linear with a target quantity over a 4 log dynamic range (from 105 to 100 cell equivalents per 100 ml). In order to confirm the scope of application of such alternative methods, 80 and 85 seawater samples from the Atlantic Ocean and Mediterranean sea were analysed by both RT-qPCR and ISO culture-based methods for E. coli and Enterococcus spp. enumerations. This study demonstrates that by giving reliable results in 3 h, the RT-qPCR method has high potential as a rapid test for recreational water quality monitoring. In natural waters, significant linear log-log relations between the RT-qPCR and culture method measurements for E. coli and Enterococcus spp. assays were shown (correlation coefficient (r) values of 0.814 and 0.715, p < 0.0001, respectively). The sensitivities (defined as the probability of a sample testing positive if the criterion number is exceeded) of RT-qPCR for E. coli and Enterococcus spp. were respectively 94.4% and 83.9%. By contrast, specificities (defined as the probability of a test being negative if a contamination is truly absent) could be considered as lower (65.9% and 50.0% for E. coli and Enterococcus spp.). This reflects that RT-qPCR assays detect all viable cells (culturable and non-culturable) whereas culture methods only detect cells which are viable and culturable. (C) 2011 Elsevier GmbH. All rights reserved.

关键词： Bathing water rapid quantification RT-qPCR E. coli Enterococci

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A QUICK, SIMPLE AND UNBIASED METHOD TO QUANTIFY C2C12 MYOGENIC DIFFERENTIATION

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MUSCLE & NERVE 2011年第3期44卷 366-370页

作者： Velica, Pedro Bunce, Chris M. Univ Birmingham Sch Biosci Birmingham B15 2TT W Midlands England

Introduction: C2C12 myoblasts undergo in vitro myogenesis to form protein-rich multinucleated myotubes. Determining the fraction of total nuclei incorporated into myotubes is a commonly used method to quantify the extent of differentiation, but it is labor-intensive and susceptible to operator bias. Methods: We have developed a simple method to quantify myotube formation using micrographs of Jenner-Giemsastained C2C12 cultures. Because myotubes are darkly stained by Jenner-Giemsa dyes, the extent of myotube formation correlates with an increase in pixels attributed to the darkest tones. Thus, image histograms were obtained from photographs using ImageJ software, and the sum of the darkest tones was used as a measure of myotube density. Results: Measurements of myotube density mirrored those of fusion index during C2C12 differentiation and after treatment with prostaglandin D2, an inhibitor of C2C12 myogenesis. Conclusions: We propose this inexpensive, quick, and unbiased method to quantify C2C12 differentiation as a complement of the fusion index analysis. Muscle Nerve 44: 366-370, 2011

关键词： fusion index in vitro myoblast myotube rapid quantification

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rapidly quantification of intact infectious H1N1 virus using ICA-qPCR and PMA-qPCR

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Biosafety and Health 2024年第6期6卷 327-336页

作者： Chudan Liang Zequn Wang Linjin Fan Yulong Wang Yuandong Zhou Xiaofeng Yang Jingyan Lin Pengfei Ye Wendi Shi Hongxin Huang Huijun Yan Linna Liu Jun Qian Zhongshan School of Medicine Sun Yat-sen UniversityGuangzhou 510080China Institute of Infectious Disease Guangzhou Eighth People’s HospitalGuangzhou Medical UniversityGuangzhou 510440China School of Public Health(Shenzhen) Sun Yat-sen UniversityShenzhen 514400China Shenzhen Key Laboratory of Pathogenic Microbes and Biosafety Shenzhen 514400China Guangdong Provincial Highly Pathogenic Microorganism Science Data Center Guangzhou 510440China

The increase in emerging and reemerging infectious diseases has underscored the need for the prompt monitoring of intact infectious viruses and the quick assessment of their ***,molecular techniques cannot distinguish between intact infectious and noninfectious ***,two distinct methodologies have been developed for the expeditious and dependable quantification of intact infectious H1N1 virus,and several experiments have been conducted to substantiate their *** is an integrated cell absorption quantitative polymerase chain reaction(qPCR)method(ICA-qPCR),and the other is a combined propidium monoazide qPCR method(PMA-qPCR).The quantification limit is 100 cell culture infective dose 50%(CCID50)/mL in ICA-qPCR following a 1.5-hour cell absorption or 126 CCID50/mL after a 15-minute *** PMA-qPCR,the limit was 2,512 CCID50/*** number of genome copies quantified by the ICA-qPCR and PMA-qPCR methods was strongly correlated with the infectious titer determined by the CCID50 assay,thereby enabling the estimation of virus *** ICA-qPCR and PMA-qPCR methods are both suitable for the identification and quantification of intact infectious H1N1 virus in inactivated samples,wastewater,and biological *** conclusion,the ICA-qPCR and PMA-qPCR methods have distinct advantages and disadvantages,and can be used to quantify intact infectious viruses *** methodologies can facilitate the identification of the presence of intact infectious viruses in wastewater or on pathogen-related physical surfaces in high-level biosafety laboratories and medical ***,these methodologies can also be utilized to detect other highly pathogenic pathogens.

关键词： Intact infectious virus rapid quantification Integrated cell absorption quantitative polymerase chain reaction(ICA-qPCR) Propidium monoazide quantitative polymerase chain reaction(PMA-qPCR) Inactivation

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quantification of artificial sweeteners in alcoholic drinks using direct analysis in real-time QTRAP mass spectrometry

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FOOD CHEMISTRY 2021年 342卷 128331-128331页

作者： Li, Xiaomin Li, Shuangqing Li, Hongmei Wang, Jing Luo, Qin Yin, Xiong Natl Inst Metrol China Lab Food Safety Div Metrol Chem Beijing 100029 Peoples R China Beijing Univ Chem Technol State Key Lab Chem Resource Engn Beijing Adv Innovat Ctr Soft Matter Sci & Engn Coll Chem Beijing 100029 Peoples R China

Artificial sweeteners have been widely used as replacements for sugars in foods. rapid determination of artificial sweeteners contained in various foods are highly desirable for the routine analysis. Here, we report a robust approach based on direct analysis in real time coupled with QTRAP mass spectrometry to screen and quantitate simultaneously seven artificial sweeteners, including aspartame, saccharin, acesulfame-K, neotame, sucralose, cyclamate and alitame in alcoholic drinks. The detection method merely involved a simple sample pretreatment process, with a good linearity, low limit of quantification, satisfied recovery and relative standard deviation for each target compound. More importantly, the approach is highly sensitive and accurate in monitoring the seven artificial sweeteners in whisky, Chinese liquors, beer and wines obtained from the supermarket. The results demonstrated that the approach described here could be suitable for large-scale application in routine quality control analysis of artificial sweeteners.

关键词： Artificial sweeteners Alcoholic drinks Direct analysis in real time (DART) QTRAP mass spectrometry rapid quantification Matrix effect

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Selective detection of starch in banana fruit with Raman spectroscopy

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FOOD CHEMISTRY 2023年 401卷 134166页

作者： Nakajima, Shusaku Kuroki, Shinichiro Ikehata, Akifumi Kobe Univ Grad Sch Agr Sci I-1 Rokkodai Cho Kobe Hyogo 6578501 Japan Natl Agr & Food Res Org Food Res Inst 2-1-12 Kannondai Tsukuba Ibaraki 3058642 Japan

To develop an analytical method for rapid quantification of starch in agricultural produce, we measured the Raman spectra of ripening banana fruit and compared the obtained data to those of standard starch, sugar, and fiber chemical samples. Standard starches exhibited distinctive Raman bands, which were similar to the spectral features in green banana before ripening. Moreover, these banana-derived Raman bands gradually weakened during 10 d of storage. Standard sugars (glucose, sucrose, and fructose) exhibited Raman bands in both solid and liquid states, whereas standard fibers exhibited broad spectra and no such bands. Although the sugar content increased, no sugar bands were observed in the banana fruit even after ripening. A correlation was found between the Raman bands and starch content obtained by chemical analysis. These results demonstrate that Raman spectroscopy can selectively provide information regarding starch in banana fruit and be applied as an analytical method for rapid starch quantification.

关键词： Starch Raman spectroscopy rapid quantification Banana

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Development and validation of a real-time and non-destructive method for direct measurement of solid mixture based on reflection spectra

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JOURNAL OF CLEANER PRODUCTION 2022年 378卷

作者： Liu, Yong Duan, Ning Xu, Fuyuan Jiang, Linhua Cheng, Wen Xu, Yanli Zhu, Guangbin Anhui Univ Sci & Technol Sch Mat Sci & Engn Huainan 232001 Anhui Peoples R China Tongji Univ Coll Environm Sci & Engn State Key Lab Pollut Control & Resources Reuse Shanghai 200092 Peoples R China Shanghai Inst Pollut Control & Ecol Secur Shanghai 200092 Peoples R China Tianjin Univ Sch Environm Sci & Engn Tianjin 300350 Peoples R China

The Belt and Road countries are facing low resource exploitation efficiency and environmental pollution prob-lems in the field of industrialization and production. Real-time and accurate determination of solid composition is urgently required. Herein, a new quantitative model and method were developed based on the mass conser-vation law, the elementary reaction and interaction between light and substance. Charge-coupled Device receiver was used to directly measure the solids and quickly obtain the spectral reflectance. According to the difference of spectral reflectance, partial least squares mathematical iterative fitting is utilized to optimize the model pa-rameters based on the relationship between concentration and reflectance at 380-740 nm. It is applied to three typical mineral systems: I. Fe2O3 and Fe3O4 system with different metal valence states;II. ZnO and ZnS system with different anions;and III. Fe2O3 and ZnS system with different element compositions. The best characteristic wavelengths are 560 nm, 720 nm and 680 nm. The goodness of fit is 0.97-0.99 with root mean square less than 0.04, standard recoveries 98%-108%, and relative error of blind sample less than 5%. Compared with some conventional solid analysis methods, this method has the advantages of real-time, non-destructive, no pre-treatment and no secondary pollution.

关键词： Solid Reflectance Model Nondestructive direct measurement rapid quantification

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Determination of MCPA in environmental samples using an analytical on-line system based on imprinted poly[2-(3-butenyl)-2-oxazoline] and ambient ionization mass spectrometry

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SENSORS AND ACTUATORS B-CHEMICAL 2024年 403卷

作者： Lusina, Aleksandra Ceglowski, Michal Adam Mickiewicz Univ Fac Chem Uniwersytetu Poznanskiego 8 61614 Poznan Poland

Monitoring and quantifying organic chemicals in the environment play a vital role in understanding their behavior and ensuring environmental safety. MCPA (2-methyl-4-chlorophenoxyacetic acid) is a commonly used phenoxy herbicide that poses potential risks to aquatic life. In this study, we present an innovative analytical approach for MCPA quantification, employing molecularly imprinted polymers (MIPs) for selective extraction and ambient plasma mass spectrometry for direct on-line analysis. To synthesize functional MIPs, we employed a post-polymerization strategy based on a thiol-ene click reaction conducted on a short-chain poly[2-(3-butenyl)-2oxazoline] (poly(ButenOx)) that allowed attachment of 3-mercaptopropionic acid (MPA) to polymer side chains. The incorporation of MPA groups into polymer structure enabled the attainment of elevated maximum adsorption capacities and enhanced selectivity towards MCPA. Utilizing a specially designed ambient plasma mass spectrometry setup, we successfully quantified MCPA in water samples, achieving significantly improved detection limits compared to conventional solution-based analysis, whereas the quantification of MCPA in reallife river water samples demonstrated excellent recoveries. In conclusion, this novel analytical method employing MIPs and ambient plasma mass spectrometry provides an effective and sensitive approach for accurate MCPA detection in environmental water samples. The technique holds promise for facilitating reliable monitoring and management of MCPA levels in aquatic ecosystems.

关键词： Poly(2-oxazoline) MCPA Selective adsorption rapid quantification Molecularly imprinted polymer

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