Spectroscopic evidence of spin-state excitation in d-electron correlated semiconductor FeSb2.

Iron antimonide (FeSb2) has been investigated for decades due to its puzzling electronic properties. It undergoes the temperature-controlled transition from an insulator to an ill-defined metal, with a cross-over from diamagnetism to paramagnetism. Extensive efforts have been made to uncover the underlying mechanism, but a consensus has yet to be reached. While macroscopic transport and magnetic measurements can be explained by different theoretical proposals, the essential spectroscopic evidence required to distinguish the physical origin is missing. In this paper, through the use of X-ray absorption spectroscopy and atomic multiplet simulations, we have observed the mixed spin states of 3d 6 configuration in FeSb2. Furthermore, we reveal that the enhancement of the conductivity, whether induced by temperature or doping, is characterized by populating the high-spin state from the low-spin state. Our work constitutes vital spectroscopic evidence that the electrical/magnetical transition in FeSb2 is directly associated with the spin-state excitation.

Anaplasma phagocytophilum in Marmota himalayana.

BACKGROUND: Human granulocytic anaplasmosis is a tick-borne zoonotic disease caused by Anaplasma phagocytophilum. Coinfections with A. phagocytophilum and other tick-borne pathogens are reported frequently, whereas the relationship between A. phagocytophilum and flea-borne Yersnia pestis is rarely concerned. RESULTS: A. phagocytophilum and Yersnia pestis were discovered within a Marmota himalayana found dead in the environment, as determined by 16S ribosomal rRNA sequencing. Comparative genomic analyses of marmot-derived A. phagocytophilum isolate demonstrated its similarities and a geographic isolation from other global strains. The 16S rRNA gene and GroEL amino acid sequence identity rates between marmot-derived A. phagocytophilum (JAHLEX000000000) and reference strain HZ (CP000235.1) are 99.73% (1490/1494) and 99.82% (549/550), respectively. 16S rRNA and groESL gene screenings show that A. phagocytophilum is widely distributed in marmots; the bacterium was more common in marmots found dead (24.59%, 15/61) than in captured marmots (19.21%, 29/151). We found a higher Y. pestis isolation rate in dead marmots harboring A. phagocytophilum than in those without it (2 = 4.047, p < 0.05). Marmot-derived A. phagocytophilum was able to live in L929 cells and BALB/c mice but did not propagate well. CONCLUSIONS: In this study, A. phagocytophilum was identified for the first time in Marmota himalayana, a predominant Yersinia pestis host. Our results provide initial evidence for M. himalayana being a reservoir for A. phagocytophilum; moreover, we found with the presence of A. phagocytophilum, marmots may be more vulnerable to plague. Humans are at risk for co-infection with both pathogens by exposure to such marmots.

Smartphone-imaged multilayered paper-based analytical device for colorimetric analysis of carcinoembryonic antigen.

Paper-based immunoassays are effective methods that employ microfluidic paper-based analytical devices (µPADs) for the rapid, simple, and accurate quantification of analytes in point-of-care diagnosis. In this study, we developed a wax-printed multilayered µPAD for the colorimetric detection of carcinoembryonic antigen (CEA), where the device contained a movable and rotatable detection layer to allow the µPAD to switch the state of the sample solutions, i.e., flowing or storing in the sensing zones. A smartphone with a custom-developed program served as an automated colorimetric reader to capture and analyze images from the µPAD, before calculating and displaying the test results. After optimizing the crucial conditions for the assay, the proposed method exhibited a wide linear dynamic range from 0.5 to 70 ng/mL, with a low CEA detection limit of 0.015 ng/mL. The clinical performance of this method was successfully validated using 50 positive and 40 negative human serum samples, thereby demonstrating the high sensitivity of 98.0% and specificity of 97.5% in the detection of CEA. The proposed method is greatly simplified compared with the cumbersome steps required for traditional immunoassays, but without any loss of accuracy and stability, as well as reducing the time needed to detect CEA. Complex and bulky instruments are replaced with a smartphone. The proposed detection platform could potentially be applied in point-of-care testing. Graphical abstract.

Algorithms for immunochromatographic assay: review and impact on future application.

Lateral flow immunoassay (LFIA) is a critical choice for applications of point-of-care testing (POCT) in clinical and laboratory environments because of its excellent features and versatility. To obtain authentic values of analyte concentrations and reliable detection results, the relevant research has featured the application of a diversity of methods of mathematical analysis to technical analysis to allow for use with a small quantity of data. Accordingly, a number of signal and image processing strategies have also emerged for the application of gold immunochromatographic and fluorescent strips to improve sensitivity and overcome the limitations of correlative hardware systems. Instead of traditional methods to solve the problem, researchers nowadays are interested in machine learning and its more powerful variant, deep learning technology, for LFIA detection. This review emphasizes different models for the POCT of accurate labels as well as signal processing strategies that use artificial intelligence and machine learning. We focus on the analytical mechanism, procedural flow, and the results of the assay, and conclude by summarizing the advantages and limitations of each algorithm. We also discuss the potential for application of and directions of future research on LFIA technology when combined with Artificial Intelligence and deep learning.

Simultaneous quantification of α-lactalbumin and ß-casein in human milk using ultra-performance liquid chromatography with tandem mass spectrometry based on their signature peptides and winged isotope internal standards.

In recent years, there is an increasing need to measure the concentration of individual proteins in human milk, instead of total human milk proteins. Due to lack of human milk protein standards, there are only few quantification methods established. The objective of the present work was to develop a simple and rapid quantification method for simultaneous determination of α-lactalbumin and ß-casein in human milk using signature peptides according to a modified quantitative proteomics strategy. The internal standards containing the signature peptide sequences were synthesized with isotope-labeled amino acids. The purity of synthesized peptides as standards was determined by amino acid analysis method and area normalization method. The contents of α-lactalbumin and ß-casein in human milk were measured according to the equimolar relationship between the two proteins and their corresponding signature peptides. The method validation results showed a satisfied linearity (R(2)>0.99) and recoveries (97.2-102.5% for α-lactalbumin and 99.5-100.3% for ß-casein). The limit of quantification for α-lactalbumin and ß-casein was 8.0mg/100g and 1.2mg/100g, respectively. CVs for α-lactalbumin and ß-casein in human milk were 5.2% and 3.0%. The contents of α-lactalbumin and ß-casein in 147 human milk samples were successfully determined by the established method and their contents were 205.5-578.2mg/100g and 116.4-467.4mg/100g at different lactation stages. The developed method allows simultaneously determination of α-lactalbumin and ß-casein in human milk. The quantitative strategy based on signature peptide should be applicable to other endogenous proteins in breast milk and other body fluids.

[An etiological survey on a foodborne disease epidemic outbreak caused by Salmonella enteritidis].

OBJECTIVE: To conduct an etiological molecular epidemiological survey and laboratory test on a foodborne disease epidemic outbreak to make clear of the cause and implement effective prevention and control on it. METHODS: On May 12th 2012, 135 kindergarten children were sent to Xuzhou City People's Hospital and Children's Hospital with gastrointestinal infection disease. A total of 34 anus swab samples and 4 vomit samples were collected from the patients. Real-time PCR rapid detection, strains separation and cultivation, phage lysis experiments, ATB automated identification system were used to make etiological detection and identification. The genomic DNA of salmonella enteritidis were typed with the pulsed-field gel electrophoresis (PFGE), cluster analysis were carried out together with the patterns of local Salmonella infections. RESULTS: Children in 20 classes were suffered from the gastrointestinal infection among the 21 classes. There were no significant aggregation of class distribution. Among the 135 patients, 76 were boys (56.3%) and 59 were girls (43.7%). The main symptoms were fever (above 38°C), diarrhea and bellyache. Through real-time PCR detection and strains separation, 19 salmonella enteritidis were isolated from 34 anus swab samples of suspected cases and the detection rate was 56%. There were no strains detected from vomit samples. All of the 19 salmonella enteritidis showed the same serological subtype, biochemical reaction, drug sensitivity and phage lysis pattern. The salmonella enteritidis had the identical PFGE pattern (100% similarity), and were different from the pattern of local sporadic infection cases. CONCLUSION: It was confirmed that this was an epidemic outbreak of foodborne disease caused by homologous salmonella enteritidis by epidemiological survey, clinical information, lab etiological test and molecular typing.

Liquid Chromatography-Tandem Mass Spectrometry Analysis of Aminoglycosides in Foods Using an Ethylene-Bridged Hybrid Zwitterionic Stationary Phase and Hydrophilic-Lipophilic-Balanced Solid-Phase Extraction Cartridges.

This work aimed to develop an analytical method for the screening of multiple aminoglycoside residues in foods of animal origin using an ethylene-bridged hybrid (BEH) particle-based sulfoalkylbetaine stationary phase. The effects of chromatographic conditions on the separation of 17 aminoglycosides have been systematically investigated. Sample preparation and mass spectrometry detection have also been investigated and optimized. In contrast to high buffer concentrations in the mobile phase required for silica-based sulfoalkylbetaine stationary phases, a moderate buffer concentration (20 mM) provided the optimal separation of 17 aminoglycosides with the BEH sulfoalkylbetaine stationary phase. The developed method has been evaluated in milk, beef, pork, liver, and honey samples with good performance for retention, selectivity, sensitivity, linearity, precision, and accuracy. The majority of the limit of quantitation estimated with the matrix was less than 25 µg/kg. The overall accuracy across five matrices was in the range from 96 to 111%, with standard deviations of less than 19%.

Separation of Nonivamide and Capsaicin by Ultrahigh-Performance Liquid Chromatography for Routine Analysis of Capsaicinoids in Capsicum Products.

BACKGROUND: Baseline separation of nonivamide (NON) and capsaicin (CAP) has not been achieved by using the existing liquid chromatography (LC) methods for the capsaicinoid analysis. This could lead to large errors in the determination of capsaicinoids for capsicum products. OBJECTIVE: The development of an ultrahigh-performance liquid chromatography (UHPLC) method that simultaneously separates NON and CAP as well as other capsaicinoids for the routine analysis of capsaicinoids in capsicum products. METHOD: Capsaicinoids were separated on a Waters CORTECSTM T3 Column (2.1 mm i.d. × 150 mm, 1.6 µm particle size) that was maintained at 45°C on a UHPLC system with a 3-step gradient elution using a binary mobile phase system consisting of water and acetonitrile. Florescence detection was set at 280 nm excitation wavelength and 325 nm emission wavelength. RESULTS: The UHPLC method was able to simultaneously separate NON and CAP, with a minimum resolution of 1.5, as well as other seven capsaicinoids with a total run time of 27 min. Method selectivity, robustness, accuracy, and precision were evaluated, and excellent performance was achieved. CONCLUSIONS: The UHPLC method for NON and CAP and other seven capsaicinoids has been successfully developed and found suitable for the routine analysis of capsaicinoids. HIGHLIGHTS: For the first time, NON and CAP are well separated (Rs >1.5) in a 27 min LC separation. This UHPLC method offers a suitable solution for the determination of nine capsaicinoids in QC labs.

Prevalence of Yersinia enterocolitica in pigs slaughtered in Chinese abattoirs.

The distribution of Yersinia enterocolitica in slaughtered pigs in China was studied. A total of 8,773 samples were collected and examined from different pig abattoirs in 11 provinces from 2009 to 2011. Of these, 4,495 were oral-pharyngeal swab (tonsils) samples from pigs, 1,239 were from intestinal contents, and 3,039 were feces samples from abattoirs or local pigpens. The data showed that 1,132 strains were obtained, from which the isolation rate for Yersinia enterocolitica was 19.53% (878/4,495) from the tonsil samples, 7.51% (93/1,239) from intestinal contents, and 5.30% (161/3,039) from feces. Of the 850 pathogenic Yersinia strains, except for three of bioserotype 2/O:9 and three of bioserotype 4/O:3, most (844/850) were of bioserotype 3/O:3. Interestingly, pathogenic Y. enterocolitica accounted for the majority of the isolated strains from most provinces (85.17% to 100%), whereas from Heilongjiang, 96.52% (111/115) were classified as nonpathogenic biotype 1A with various serotypes, and only 3.48% of the strains (4/115) were pathogenic 3/O:3. All of the pathogenic strains were analyzed using pulsed-field gel electrophoresis (PFGE), and 49 patterns were obtained for the O:3 pathogenic strains; most of them were K6GN11C30021 (53.13%: 450/847) and K6GN11C30012 (21.37%: 181/847). Several strains from diarrhea patient samples revealed PFGE patterns identical to that from samples of local pigs, suggesting a possible link between porcine isolates and human infection. The results above suggested that Yersinia enterocolitica in slaughtered pigs from Chinese abattoirs was characterized by region-specific PFGE patterns and confirmed that strains isolated from pigs are closely related to those from human infections.

Evaluation of hybrid surface technology for the analysis of the B-group vitamins by LC-ESI-MS/MS.

Recently, a novel hybrid surface technology (HST) has been developed to mitigate metal analyte adsorption in liquid chromatography. The HST provides a hybrid organic-inorganic surface on the metal fluidic path, from injection to detector and including the column frits and wall, to mitigate the interaction between analytes and metals. Here the impact of the HST on the analysis of B group vitamins using liquid chromatography coupled with electrospray tandem mass spectrometry (LC-ESI-MS/MS) has been evaluated. Significant improvements in analyte intensity, limit of quantification (LOQ), carry-over, and peak shape were observed using an LC-ESI-MS/MS system and column that incorporated the HST. The key observed improvements include a 3-10 times increase in sensitivity (providing a lower LOQ) for riboflavin, thiamine, nicotinamide, FMN, PLP, and 5MTHF, no carry-over, and a more symmetrical peak for thiamine. When applied to the analysis of B group vitamins in energy drinks and B vitamin dietary supplement samples, the HST system demonstrated excellent accuracy and repeatability.

Determination of Free Bisphenol A in Commercially Packaged Ready-to-Consume Carbonated/Non-Carbonated and Non-Alcoholic Beverages with Immunoaffinity Column Purification and UPLC with Fluorescence Detector, First Action 2019.07.

BACKGROUND: Bisphenol A (BPA) is a chemical of concern in the food industry. There is a need for a sensitive analytical method for the determination of BPA in beverages. OBJECTIVE: To develop a method for the determination of BPA in carbonated, non-carbonated, and non-alcoholic drinks. METHOD: Replicates of a carbonated soft drink, orange juice with pulp, and a dairy-based coffee drink at spiking levels ranging from 0 to 32 ng/mL were analyzed. The carbonated soft drink was adjusted to pH 7.4 and diluted with phosphate buffered saline (PBS). The orange juice with pulp and the dairy-based coffee drink were extracted with methanol and sodium chloride, then diluted with PBS. RESULTS: LOD ranged from 0.06 to 0.08 ng/mL and LOQ ranged from 0.10 to 0.14 ng/mL. Recoveries of BPA from all sample types at 1 to 16 ng/mL spiked levels were between 93 and 100%; relative standard deviation (RSDr, %) ranged from 0.71 to 8.38% depending on matrix and spiking levels. CONCLUSIONS: The results indicate that the method for determination of BPA in carbonated, non-carbonated, and non-alcoholic drinks is reproducible and meets AOAC Official MethodSM performance criteria. HIGHLIGHTS: The test portions were filtered and the filtrates applied to an immunoaffinity column (IAC) containing antibodies specific for BPA. After the column was washed with water, BPA was eluted from the IAC with 80% methanol and the eluate was directly injected, or concentrated and injected, into ultra-performance liquid chromatography (UPLC) with fluorescence detector (FLD) for separation, detection, and quantitation.

Exploration of the potential mechanism of Banxia Xiexin Decoction for the effects on TNBS-induced ulcerative colitis rats with the assistance of network pharmacology analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Banxia Xiexin Decoction (BXD), an ancient TCM prescription originating from Treatise on Febrile Diseases (Shang Han Lun) of the Han Dynasty, has been widely used in modern clinical practice, especially for gastrointestinal diseases, including ulcerative colitis (UC). However, the modern decoction method of BXD differs from that of the original method. Thus, an exploration of the influence of the different decoction methods on the pharmacological effects is interesting and significant. AIM OF THE STUDY: This study aimed to systematically compare the pharmacological effects of extracts of BXD on TNBS induce UC rats that were prepared by different methods, the ancient method and the modern method. The findings may provide important information for the further mechanical exploration of the classical prescription, contributing to the rational application and enhancing the understanding of BXD in modern applications or scientific research. METHODS: Fifty-four SD rats were randomly divided into the following nine groups at n = 6/group: control group; model group; salicylazosulfapyridine group; BXD ancient extraction method's low-dose group (BXD-AED-L, 3.6 g BXD-AED/kg), medium-dose group (BXD-AED-M, 7.2 g BXD-AED/kg), and high-dose group (BXD-AED-H, 14.4 g BXD-AED/kg); and BXD modern extraction method's low-dose group (BXD-MED-L, 1 g BXD-MED/kg), medium-dose group (BXD-MED-M, 2 g BXD-MED/kg), and high-dose group (BXD-MED-H, 4 g BXD-MED/kg). All the groups, except the control group, were rectally injected with 70 mg/kg ethanol solution containing TNBS (2,4,6-trinitrobenzenesulfonic acid) to establish the UC models. The pharmacological evaluations including disease activity index, colon weight index, macroscopic and histological evaluation of colon damage, and inflammatory cytokine levels (IL-4, IL-10, IL-1ß, TNF-α, and IL-6)were measured. In the network pharmacology analysis, the "herbs-components-targets-disease" network was constructed and visually analyzed with which the targets with a strong correlation with UC were screened out. RESULTS: The results showed that both BXD-AED and BXD-MED might alleviate the severity of UC with different degrees according to the majority of indices that were evaluated. At similar doses, the BXD-AED groups performed better compared with the BXD-MED groups. With the assistance of the network pharmacology analysis, some key active components (quercetin, baicalein, wogonin, and baicalin) related to the anti-UC/inflammation were screened out. The contents of the components in BXD-AED were higher than those in BXD-MED. The joint results of the study indicated that BXD, an ancient TCM compound prescription, is an effective drug candidate for the modern treatment of UC.

A Lytic Yersina pestis Bacteriophage Obtained From the Bone Marrow of Marmota himalayana in a Plague-Focus Area in China.

A lytic Yersinia pestis phage vB_YpP-YepMm (also named YepMm for briefly) was first isolated from the bone marrow of a Marmota himalayana who died of natural causes on the Qinghai-Tibet plateau in China. Based on its morphologic (isometric hexagonal head and short non-contractile conical tail) and genomic features, we classified it as belonging to the Podoviridae family. At the MOI of 10, YepMm reached maximum titers; and the one-step growth curve showed that the incubation period of the phage was about 10 min, the rise phase was about 80 min, and the lysis amount of the phage during the lysis period of 80 min was about 187 PFU/cell. The genome of the bacteriophage YepMm had nucleotide-sequence similarity of 99.99% to that of the Y. pestis bacteriophage Yep-phi characterized previously. Analyses of the biological characters showed that YepMm has a short latent period, strong lysis, and a broader lysis spectrum. It could infect Y. pestis, highly pathogenic bioserotype 1B/O:8 Y. enterocolitica, as well as serotype O:1b Y. pseudotuberculosis-the ancestor of Y. pestis. It could be further developed as an important biocontrol agent in pathogenic Yersinia spp. infection.

blaNDM and mcr-1 to mcr-5 Gene Distribution Characteristics in Gut Specimens from Different Regions of China.

Antibiotic resistance has become a global public health concern. To determine the distribution characteristics of mcr and blaNDM in China, gene screening was conducted directly from gut specimens sourced from livestock and poultry, poultry environments, human diarrhea patients, and wild animals from 10 regions, between 2010-2020. The positive rate was 5.09% (356/6991) for mcr and 0.41% (29/6991) for blaNDM, as detected in gut specimens from seven regions, throughout 2010 to 2019, but not detected in 2020. The detection rate of mcr showed significant differences among various sources: livestock and poultry (14.81%) > diarrhea patients (1.43%) > wild animals (0.36%). The detection rate of blaNDM was also higher in livestock and poultry (0.88%) than in diarrhea patients (0.17%), and this was undetected in wildlife. This is consistent with the relatively high detection rate of multiple mcr genotypes in livestock and poultry. All instances of coexistence of the mcr-1 and blaNDM genes, as well as coexistence of mcr genotypes within single specimens, and most new mcr subtypes came from livestock, and poultry environments. Our study indicates that the emergence of mcr and blaNDM genes in China is closely related to the selective pressure of carbapenem and polymyxin. The gene-based strategy is proposed to identify more resistance genes of concern, possibly providing guidance for the prevention and control of antimicrobial resistance dissemination.

A convenient polyculture system that controls a shrimp viral disease with a high transmission rate.

Developing ecological approaches for disease control is critical for future sustainable aquaculture development. White spot syndrome (WSS), caused by white spot syndrome virus (WSSV), is the most severe disease in cultured shrimp production. Culturing specific pathogen-free (SPF) broodstock is an effective and widely used strategy for controlling WSS. However, most small-scale farmers, who predominate shrimp aquaculture in developing countries, cannot cultivate SPF shrimp, as they do not have the required infrastructure and skills. Thus, these producers are more vulnerable to WSS outbreaks than industrial farms. Here we developed a shrimp polyculture system that prevents WSS outbreaks by introducing specific fish species. The system is easy to implement and requires no special biosecurity measures. The promotion of this system in China demonstrated that it allowed small-scale farmers to improve their livelihood through shrimp cultivation by controlling WSS outbreaks and increasing the production of ponds.

Pathogenic strains of Yersinia enterocolitica isolated from domestic dogs (Canis familiaris) belonging to farmers are of the same subtype as pathogenic Y. enterocolitica strains isolated from humans and may be a source of human infection in Jiangsu Province, China.

We isolated 326 Yersinia enterocolitica strains from 5,919 specimens from patients with diarrhea at outpatient clinics, livestock, poultry, wild animals, insect vectors, food, and the environment in the cities of Nantong and Xuzhou in Jiangsu Province, China, from 2004 to 2008. The results showed that the 12 pathogenic strains were of the O:3 serotype. Six strains were isolated from domestic dogs (Canis familiaris) belonging to farmers and were found to be the primary carriers of pathogenic Y. enterocolitica strains, especially in Xuzhou. Pulsed-field gel electrophoresis analysis of the pathogenic strains from dogs belonging to farmers showed that they shared the same patterns as strains from diarrhea patients isolated in 1994. This indicates that the strains from domestic dogs have a close correlation with the strains causing human infections.

Detection platforms for point-of-care testing based on colorimetric, luminescent and magnetic assays: A review.

Along with the considerable potential and increasing demand of the point-of-care testing (POCT), corresponding detection platforms have attracted great interest in both academic and practical fields. The first few generations of conventional detection devices tend to be costly, complicated to operate and hard to move on account of early limitations in the level of technological development and relatively high requirement of performance. Owing to the requirements for rapidity, simplicity, accuracy and cost controlling in the POCT, reader systems are urgently needed to be developed, upgraded and modified constantly, realizing on-site testing and healthcare management without a specific place or cumbersome operation. Accordingly, numerous rapid detection platforms with diverse size and performance have emerged such as bench-top apparatuses, handheld devices and intelligent detection devices. This review discusses various devices developed mainly for the detection of lateral flow test strips (LFTSs) or microfluidic strips in the POCT and summarizes these devices by size and portability. Furthermore, on the basis of various detection methods and diverse probes usually containing specific nanoparticles composites, three most common aspects of detection rationale in the POCT are selected to elaborate each kind of detection platforms in this paper: colorimetric assay, luminescent detection and magnetic signal detection. Herein, we focus on their structures, detection mechanisms and assay results, accompany with discussions and comments on the performances, costs and potential application, as well as advantages and limitations of each technique. In addition, perspectives on the future advances of detection platforms and some conclusions are proposed.

O:8 serotype Yersinia enterocolitica strains in China.

Serotypes O:3, O:8 and O:9 Yersinia enterocolitica strains carrying virulence determinants are common pathogens causing human infections. In many years of surveillance in China for Y. enterocolitica, no pathogenic O:8 strains have been found where the isolated O:8 serotypes lacked the major virulence genes and in contrast to O:3 and O:9 strains, none of the O:8 isolates were from humans. These O:8 isolates lack ail, ystA, yadA and virF genes but possess the ystB gene and all belong to Biotype 1A. These O:8 strains did not kill mice and could protect immunized mice against challenge with a pathogenic O:8 strain. Compared to the Chinese pathogenic O:3 and O:9 strains which have similar pulsed-field gel electrophoresis patterns, the 39 Chinese O:8 animal and food isolates were different from the pathogenic O:8 reference strains. This suggests the O:8 strains lacking virulence determinants may not disseminate rapidly in humans and are maintained in animal reservoirs; and therefore exhibit higher variance and divergence from the virulent type.

Quantification of bovine ß-casein allergen in baked foodstuffs based on ultra-performance liquid chromatography with tandem mass spectrometry.

The quantification of allergens in food including baked food matrices is of great interest. The aim of the present study was to describe a non-immunologic method to quantify bovine ß-casein using ultra-performance liquid chromatography tandem triple quadrupole mass spectrometry (UPLC-TQ-MS/MS) in multiple reaction monitoring (MRM) mode. Eight of 10 theoretical peptides from ß-casein after tryptic digestion were compared and MRM methods were developed to determine five signature peptides. The peptide VLPVPQK was selected as the signature peptide for bovine ß-casein because of the high sensitivity. A stable isotope-labelled internal standard was designed to adjust the instability of sample pre-treatment and ionisation caused by matrix effect. Using the present suspension digestion method, the native and denatured ß-casein could be digested to release the signature peptide at the maximum extent. The UPLC-TQ-MS/MS method developed based on a tryptic signature peptide led to a reliable determination of bovine ß-casein allergen in baked food matrices at a low quantitation level down to 500 µg kg(-1) with a satisfactory accuracy (< 8.9%) and recovery (98.8% ± 2.6% to 106.7% ± 3.0%).

Biomonitoring heavy metal contaminations by moss visible parameters.

Traditional sampling for heavy metal monitoring is a time-consuming and inconvenient method, which also does not indicate contaminants non-invasively and instantaneously. Moss is sensitive to heavy metals and is therefore considered a pollution indicator. However, it is unknown what kind physiological parameters can indicate metal contaminations quickly and non-invasively. Here, we systematically examined the effects of six heavy metals on physiological parameters and photosynthetic activities of two moss species grown in aquatic media or moist soil surface. We suggest that a phenotype with anthocyanin accumulation pattern and chlorosis pattern and two chlorophyll fluorescence parameters with their images can roughly reflect metal species groups, concentrations and differences between the two moss species. In other words, metal contaminations could be roughly estimated visually using the naked eye. Enzymatic and non-enzymatic anti-oxidative abilities and photosynthetic protein contents of Eurhynchium eustegium were higher than those of Taxiphyllum taxirameum, indicating their differential metal tolerance. Neither anti-oxidative abilities nor photosynthetic proteins were found to be ideal indicators. This study provides new ideas to monitor heavy metals rapidly and non-invasively in water or on wetland and moist soil surface.