VP1-binding protein glucose-regulated protein 78 as an important mediator for enterovirus 71 infecting human brain microvascular endothelial cells

Purpose

Enterovirus 71 (EV71) is one of the main pathogens causing hand, foot and mouth disease, which could even induce severe brain damage in some patients. As the underlying mechanism of the invasion and replication process still remains largely unknown, we investigated the role of candidate proteins expressed during EV71 invasion in human brain microvascular endothelial cells (HBMECs) to delineate the pathophysiological mechanism of EV-71 infection.

Materials and Methods

Ninety-one candidate EV71-associated proteins which could bind the major capsid protein (viral protein 1 [VP1]) of EV71 on the HBMEC were identified by applying an analysis of glutathione-S-transferase pull-down coupling with liquid chromatography-electrospray ionisation-tandem mass spectrometry (LC-ESI-MS/MS). Seventy-eight kDa glucose-regulated protein 78 (GRP78) binding to the VP1 protein was further validated by co-immunoprecipitation, immunofluorescence and western blot analysis. To explore the role of GRP78 in EV71 infection, GRP78 was knocked down and overexpressed in HBMEC and was verified by TCID50 assay.

Results

LC-ESI-MS/MS-identified 91 proteins were subjected to gene ontology analysis, and on molecular and biological function analysis revealed GRP78 act as an important binding protein in mediating EV71 infection. In addition, immunofluorescence demonstrated the co-localisation of GRP78 and VP1 in cytoplasm of the infected HBMEC. The TCID50 assay showed that knockdown of GRP78 could attenuate the replication capacity of EV71 in HBMEC, and the overexpression could increase the virus titre in HBEMC at 24 h post-infection suggesting that GRP78 was associated with the replication capacity of EV71 in HBMEC.

Conclusion

These findings provided evidence that GRP78 plays an important role during the progression of EV71 infection as a mediator in HBMEC.

Searching for calcium antagonists for hypertension disease therapy from Moutan Cortex, using bioactivity integrated UHPLC-QTOF-MS

INTRODUCTION

Calcium channel blockers (CCBs) are currently the most commonly used drugs for the treatment of hypertension. Moutan Cortex (MC), a traditional Chinese herb, has been found to have an anti-hypertensive effect. However, its potential mechanisms in the regulation of intracellular calcium concentration ([Ca²⁺ ]_i ) remain poorly understood.

OBJECTIVE

The main objective of this work was to identify the potential calcium antagonists from MC and study their molecular mechanisms.

METHODS

Ultra-high performance liquid chromatography-quadrupole-time-of-fight-mass spectrometry (UHPLC-QTOF-MS) analysis combined with a dual-luciferase reporter assay was utilised to systematically screen the calcium antagonistic active ingredients in the methanol extract of MC. Additionally, the molecular mechanism of these compounds was further studied using live-cell imaging analysis with the calcium ion (Ca²⁺ ) probe dye fluo-4/AM to monitor changes in [Ca²⁺ ]_i .

RESULTS

Three monoterpenoids (paeoniflorin, benzoylpaeoniflorin and mudanpioside C), one phenolic acid (paeonol) and one gallotannin (1,2,3,4,6-O-pentagalloylglucose) were screened out as potential calcium antagonists in MC. Among them, the calcium antagonistic activity of benzoylpaeoniflorin, mudanpioside C and 1,2,3,4,6-O-pentagalloylglucose is first reported. Additionally, paeoniflorin, benzoylpaeoniflorin, mudanpioside C and paeonol can effectively block voltage-operated Ca²⁺ channels (VOCCs) to exert calcium antagonism, while 1,2,3,4,6-O-pentagalloylglucose plays a role in blocking inositol 1,4,5-trisphosphate receptors (IP3Rs).

CONCLUSION

This work indicated that the anti-hypertensive efficacy of MC acted through multiple components selectively antagonising multiple cell signalling pathways to regulate [Ca²⁺ ]_i . Furthermore, they could be considered as a reference standard for controlling the quality of Chinese medicinal materials.

Modified 2D-2D ZnIn2S4/BiOCl van der Waals heterojunctions with CQDs: Accelerated charge transfer and enhanced photocatalytic activity under vis- and NIR-light

Broadening the range of light absorption and inhibiting charge carrier's recombination are vital to improving photocatalytic activity. In this study, a novel full spectrum light-driven carbon quantum dots (CQDs) modified 2D-2D ZnIn₂S₄/BiOCl van der Waals (VDW) heterostructures were prepared by a facile hydrothermal method. It exhibits remarkable degradation efficiency for removing various antibiotics from water (i.e. tetracycline (TC), ciprofloxacin (CIP) and oxytetracycline (OTC) under visible and near-infrared (NIR) light. The enhancement of photocatalytic performance is due to the 2D-2D VDW heterostructures and CQDs not only accelerate the interfacial charge separation and transfer but also provide massive reactive canters to facilitate degradation reaction. Besides, the optical absorption capacity of CQDs modified 2D-2D ZnIn₂S₄/BiOCl VDW heterostructures are obviously enhanced because of the up-conversion photoluminescence (UC-PL) properties of CQDs. Furthermore, the degradation process of TC is assessed by three-dimensional excitation-emission matrix (3D-EEMs) and liquid chromatography-tandem mass (LC-MS/MS) spectrometry analysis. Active species trapping experiments and electron spin resonance (ESR) testify that O₂^-, OH, and holes play a crucial part in the photocatalytic degradation process. This work affords a new promising approach for CQDs modified 2D/2D VDW heterojunction with enhanced photoactivity in organic pollutant degradation for full spectrum light utilization.

HR-LC-ESI-Orbitrap-MS based metabolite profiling of Prunus dulcis Mill. (Italian cultivars Toritto and Avola) husks and evaluation of antioxidant activity

INTRODUCTION

Prunus dulcis Mill. is a plant cultivated for the production of its edible seeds, known as sweet almonds. In the last decades almond demand has highly increased due to their wide use in the industrial manufacturing of almond-based foods; this has led to a huge production of waste materials, mainly corresponding to shells and husks.

OBJECTIVE

To achieve a deeper understanding of the chemical composition of almond husks with the aim of exploring these byproducts as a source of bioactives to be used in nutraceutical and cosmetic formulations.

METHODS

Methanol, ethanol and ethanol-water extracts of the almond husks were analysed by high-resolution liquid chromatography electrospray ionisation Orbitrap mass spectrometry (HR-LC-ESI-Orbitrap-MS) in negative ion mode. Tandem mass spectrometry (MS/MS) data were acquired by using the Data-Dependent Scan experiment, allowing the precursor ion to be selected as the most intense peak during LC-MS analyses. Nuclear magnetic resonance (NMR) experiments were performed on a Bruker DRX-600 spectrometer. Folin-Ciocalteu, DPPH^• (2,2-diphenyl-1-picrylhydrazyl) and TEAC (Trolox equivalent antioxidant capacity) assays were employed to determine the total phenolic content and the radical scavenging activity of the extracts.

RESULTS

The LC-MS/MS analysis of the methanol extract guided the isolation of phloroglucinol derivatives, flavonoids and terpenes. Eco-friendly extraction methods showed to be selective in extracting flavonoids while the comparison of the LC-MS profiles of the Italian cultivars Toritto and Avola showed significant differences, confirming how different growing conditions may influence the metabolome of a plant species.

CONCLUSION

This study led to a deeper insight into the chemical constituents of almond husks and showed how the eco-friendly extraction resulted in an effective method to obtain extracts rich in antioxidant sources.

Porcine keratin 75 in developing enamel

OBJECTIVE

To provide in vivo biochemical evidence for the isolation, identification, and characterization of porcine keratin 75 (K75) in developing enamel.

METHODS

Immunolocalization of K75 was observed in mandibles from mice at postnatal days 5 and 11. K75 gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction using enamel organ epithelium (EOE) of incisors from pigs at 5 months of age. Enamel protein was extracted and isolated from both immature and mature enamel of second molars from 5-month-old pigs, and the K75 antibody-positive fraction was analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). In vitro protease digestion of K75-antibody-positive fraction was carried out using porcine kallikrein 4 (pKLK4) or recombinant human enamelysin (rhMMP20) and their degradation patterns were characterized by both SDS-PAGE and western blotting.

RESULTS

Specific immunostaining for K75 was restricted to the layers of stratum intermedium and the enamel side of ameloblasts in mice at postnatal day 5, and to the papillary layer at postnatal day 11. Porcine K75 was expressed throughout enamel formation, but its transcript levels were significantly higher in the transition EOE than in the secretory- and maturation-stage EOE. Porcine K75 was extracted from the neutral soluble fraction from both immature and mature enamel. It was identified by LC-MS/MS analysis, and was found not to be degraded by either pKLK4 or rhMMP20.

CONCLUSION

We propose that K75 is present in the developing enamel and undergoes different processing/degradation compared to other enamel proteins.

Recombinant expression, purification and characterization of acetylated LysargiNase from Escherichia coli with high activity and stability

RATIONALE

LysargiNase is a novel characterized metalloprotease that can cleave the N-terminii of lysine or arginine residues. The peptides generated by LysargiNase are just mirrors to those generated by trypsin. These characteristics of LysargiNase provide a powerful tool for mass spectrometry (MS)-based proteomics research. A highly active and stable LysargiNase produced by an easy and inexpensive method could greatly benefit proteomics research. Here, we report the soluble recombinant expression, purification and acetyl modification of LysargiNase in Escherichia coli.

METHODS

The coding sequence of LysargiNase with an enterokinase cleavage site at the N-terminus was inserted into plasmid pGEX-4 T-2 and transformed into E. coli BL21 (DE3). The strain was cultured in a 14-L fermenter with a working volume of 5 L. The protein expression was induced by adding isopropyl-β-D-thiogalactoside (IPTG) to a final concentration of 1 mM. The recombinant LysargiNase was loaded onto a GSTrap and an on-column digestion was performed to remove the GST tag and was subsequently purified by chromatographic purification. In vitro acetylation of LysargiNase was performed by using acetic anhydride. The digestion efficiency and specificity of recombinant LysargiNase and acetylated LysargiNase were compared with simple protein substrate, human serum albumin (HSA), and a complex proteomic sample, yeast lysate, by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography/tandem mass spectrometry (LC/MS/MS).

RESULTS

Highly soluble expression of recombinant LysargiNase was achieved by plasmid pGEX-4 T-2 in E. coli BL21 (DE3). In addition, acetylation of purified LysargiNase significantly increased its resistance to autolysis, which resulted in a more complete digestion of proteomics samples and more identified peptides and proteins by LC/MS/MS.

CONCLUSIONS

In this study, we constructed a highly soluble expression system for producing recombinant LysargiNase in E. coli, which gave tremendous advantages in the downstream purification process. We also confirmed that acetyl modification can increase the stability and activity of recombinant LysargiNase. The study provided a superior way to produce this powerful tool for proteomics research.

Identification of protein patterns in bovine placenta at early-mid pregnancy - Pilot studies

RATIONALE

Placenta is a crucial tissue for an appropriate development of the fetus and the course of pregnancy. Its composition and structure change dynamically along pregnancy but the full pattern of these changes is not fully described in cows yet. The aim of the present study was to detect qualitative and quantitative protein profiles of bovine placenta during early-mid pregnancy at the time of placental formation.

METHODS

Placental tissues from healthy cows (n = 3) in early pregnancy (3-5 months) were collected at the slaughterhouse. Maternal and fetal parts were manually divided prior to homogenization. Further analysis was done in triplicates on the maternal and fetal parts separately and subjected to one-dimensional (1D) electrophoretic separation, followed by identification of peptide maps by nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS). Proteins were identified by use of the MASCOT software with the SwissProt database.

RESULTS

Proteomic analysis showed more than 4000 differentially expressed proteins in maternal and fetal parts of placenta. Each part expressed around 900 proteins, of which ca. 90 were common. The identified proteins were analyzed in accordance to molecular function and their participation in biological processes.

CONCLUSIONS

The obtained results provide new insight into the knowledge about biochemical characteristics of placenta (new proteins) and serve for further studies on the possible markers of physiological/pathological pregnancy or function of placenta. Moreover, our data can be a good starting point for further studies on the processes underlying the attachment of placenta.

Intracellular Accumulation as an Indicator of Cytotoxicity to Screen Hepatotoxic Components of Chelidonium majus L. by LC-MS/MS

A novel strategy was developed to identify hepatotoxic compounds in traditional Chinese medicines (TCMs). It is based on the exposure of HL-7702 cells to a TCM extract, followed by the identification and further determination of potential hepatotoxic compounds accumulated in the cells by liquid chromatography–tandem mass spectrometry (LC–MS/MS). As a case study, potential hepatotoxic components in Chelidonium majus L. were screened out. Five alkaloids (sanguinarine, coptisine, chelerythrine, protopine, and chelidonine) were identified by LC–MS/MS within 10 min, and their intracellular concentrations were first simultaneously measured by LC–MS/MS with a run time of 4 min. A cell viability assay was performed to assess the cytotoxicity of each alkaloid. With their higher intracellular concentrations, sanguinarine, coptisine, and chelerythrine were identified as the main hepatotoxic constituents in Ch. majus. The study provides a powerful tool for the fast prediction of cytotoxic components in complex natural mixtures on a high-throughput basis.

From genomic to LC-MS/MS evidence: Analysis of PfEMP1 in Benin malaria cases

Background

PfEMP1 is the major protein from parasitic origin involved in the pathophysiology of severe malaria, and PfEMP1 domain subtypes are associated with the infection outcome. In addition, PfEMP1 variability is endless and current publicly available protein repositories do not reflect the high diversity of the sequences of PfEMP1 proteins. The identification of PfEMP1 protein sequences expressed with samples remains challenging. The aim of our study is to identify the different PfEMP1 proteins variants expressed within patient samples, and therefore identify PfEMP1 proteins domains expressed by patients presenting uncomplicated malaria or severe malaria in malaria endemic setting in Cotonou, Benin.

Methods

We performed a multi-omic approach to decipher PfEMP1 expression at the patient’s level in different clinical settings. Using a combination of whole genome sequencing approach and RNA sequencing, we were able to identify new PfEMP1 sequences and created a new custom protein database. This database was used for protein identification in mass spectrometry analysis.

Results

The differential expression analysis of RNAsequencing data shows an increased expression of the var domains transcripts DBLα1.7, DBLα1.1, DBLα2 and DBLβ12 in samples from patients suffering from Cerebral Malaria compared to Uncomplicated Malaria. Our approach allowed us to attribute PfEMP1 sequences to each sample and identify new peptides associated to PfEMP1 proteins in mass spectrometry.

Conclusion

We highlighted the diversity of the PfEMP1 sequences from field sample compared to reference sequences repositories and confirmed the validity of our approach. These findings should contribute to further vaccine development strategies based on PfEMP1 proteins.

Metabolomics for Age Discrimination of Ginseng Using a Multiplex Approach to HR-MAS NMR Spectroscopy, UPLC-QTOF/MS, and GC × GC-TOF/MS

(1) Background: The ability to determine the age of ginseng is very important because the price of ginseng depends on the cultivation period. Since morphological observation is subjective, a new scientific and systematic method for determining the age of ginseng is required. (2) Methods: Three techniques were used for a metabolomics approach. High-resolution magic-angle-spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy was used to analyze powdered ginseng samples without extraction. Ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) and gas chromatography quadrupole time-of-fight mass spectrometry (GC-TOF/MS) were used to analyze the extracts of 4-, 5-, and 6-year-old ginseng. (3) Results: A metabolomics approach has the potential to discriminate the age of ginseng. Among the primary metabolites detected from NMR spectroscopy, the levels of fumarate and choline showed moderate prediction with an area under the curve (AUC) value of more than 0.7. As a result of UPLC-QTOF/MS-based profiling, 61 metabolites referring to the VIP (variable importance in the projection) score contributed to discriminating the age of ginseng. The results of GC×GC-TOF/MS showed clear discrimination of 4-, 5-, and 6-year-old ginseng using orthogonal partial least-squares discriminant analysis (OPLS-DA) to 100% of the discrimination rate. The results of receiver operating characteristic (ROC) analysis, 16 metabolites between 4- and 5-year-old ginseng, and 18 metabolites between 5- and 6-year-old ginseng contributed to age discrimination in all regions. (4) Conclusions: These results showed that metabolic profiling and multivariate statistical analyses can distinguish the age of ginseng. Especially, it is meaningful that ginseng samples from different areas had the same metabolites for age discrimination. In future studies, it will be necessary to identify the unknown variables and to collaboratively study with other fields the biochemistry of aging in ginseng.

Effect of pH on the reaction between naringenin and methylglyoxal: A kinetic study

Methylglyoxal (MGO) is a highly reactive ɑ-dicarbonyl compound that may adversely impact food quality and human health by modifying proteins. The kinetics of the reaction of naringenin with MGO was studied at pH 6-8 and 37 °C by UV-Vis spectrophotometry and reaction products were characterized by liquid chromatography-mass spectrometry (LC-MS/MS). The apparent second order rate constant (k₂) increased at pH above the lowest pKa value of naringenin, indicating deprotonated naringenin as the main reactant. A Lederer-Manasse type reaction mechanism is suggested, with dehydration of the MGO-dihydrate as a rate determining step. The quantitative data obtained in the present study was used to simulate the competitive reaction between MGO and nucleophilic amino acid residues (Lys, Arg and Cys) and naringenin in milk. It is predicted that naringenin will be able to efficiently trap MGO during storage of milk, although the reversible trapping of MGO by Cys residues is initially kinetically favourable.

Enhanced trypsin on a budget: Stabilization, purification and high-temperature application of inexpensive commercial trypsin for proteomics applications

Trypsin is by far the most commonly used protease in proteomics. Even though the amount of protease used in each experiment is very small, digestion of large amounts of protein prior to enrichment can be rather costly. The price of commercial trypsin is highly dependent on the quality of the enzyme, which is determined by its purity, activity, and chemical modifications. In this study we evaluated several strategies for improving the quality of crude trypsin by reductive methylation and affinity purification. We present a protocol applicable to most proteomics laboratories for obtaining a highly stable and pure trypsin preparation using reductive methylation and purification by benzamidine-sepharose. The entire workflow can be performed within a day and yields ~4 mg per batch but is completely scalable. The methylated product was benchmarked against sequencing grade trypsin from Promega and they were found to be comparable for one hour digestions at elevated temperatures, where residual chymotryptic activity was found to be negligible.

External Quality Assessment Program for Newborn Screening of Amino Acids in China

BACKGROUND

To analyze the 2017 external quality assessment (EQA) results of newborn screening by MS/MS of amino acids by Chinese National Center for Clinical Laboratories, this study aimed to reflect the performance of clinical laboratories.

METHODS

Five dried blood spots were distributed to participants every round. Satisfactory performance was defined as scores more than 80 of acceptable results within the evaluation criterion. The robust coefficient of variability (RCV) of each sample was calculated by measurement systems. The chi-square () test was used to compare the correct recognition rates.

RESULTS

EQA results were collected from 150 laboratories for Ala, Val, Arg, Leu, Met, Phe, Tyr, Cit. The overall acceptable rates of the qualitative results were 87.42%, 92.72%, 73.33%, 94.04%, 92.72%, 94.70%, 92.72%, 94.04%, respectively, and the proportion of acceptable quantitative results were 76.51 %, 91.95%, 78.38 %, 92.62%, 93.29%, 93.29%, 94.63%, 91.28%, respectively. There were significant differences in the rates of acceptable quantitative results among different items and between four methods.

CONCLUSIONS

Most of the participant laboratories had satisfactory performance for the quantitative results in this EQA scheme. But for qualitative assessment, the laboratory should re-evaluate and validate their reference intervals on a regular basis to improve the consistency of clinical assessment.

Proteomic Analysis of Morphologically Changed Tissues after Prolonged Dexamethasone Treatment

Prolonged dexamethasone (Dex) administration leads to serious adverse and decrease brain and heart size, muscular atrophy, hemorrhagic liver, and presence of kidney cysts. Herein, we used an untargeted proteomic approach using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for simultaneous identification of changes in proteomes of the major organs in Sprague–Dawley (SD rats post Dex treatment. The comparative and quantitative proteomic analysis of the brain, heart, muscle, liver, and kidney tissues revealed differential expression of proteins (n = 190, 193, 39, 230, and 53, respectively) between Dex-treated and control rats. Functional network analysis using ingenuity pathway analysis (IPA revealed significant differences in regulation of metabolic pathways within the morphologically changed organs that related to: (i) brain—cell morphology, nervous system development, and function and neurological disease; (ii) heart—cellular development, cellular function and maintenance, connective tissue development and function; (iii) skeletal muscle—nucleic acid metabolism, and small molecule biochemical pathways; (iv) liver—lipid metabolism, small molecular biochemistry, and nucleic acid metabolism; and (v) kidney—drug metabolism, organism injury and abnormalities, and renal damage. Our study provides a comprehensive description of the organ-specific proteomic profilesand differentially altered biochemical pathways, after prolonged Dex treatement to understand the molecular basis for development of side effects.

Polyphenolic Profiling, Quantitative Assessment and Biological Activities of Tunisian Native Mentha rotundifolia (L.) Huds

Phenolic profiling of ten plant samples of Mentha rotundifolia (L.) Huds. collected from different bioclimatic areas of Tunisia, was for the first time carried out by using a fast ultra-high-performance liquid chromatography (UHPLC)-high resolution tandem mass spectrometry (HRMS/MS) method on a Q Exactive platform equipped with an electrospray ionization (ESI) source. An intraspecific, interpopulation variability was evidenced and a total of 17 polyphenolic metabolites were identified and quantified by using the UHPLC-HRESIMS/MS method, here validated for specificity, linearity, limit of detection, limit of quantitation, accuracy and precision. The quantitative method resulted sensitive at the nM level and reliable for rapid polyphenol quantification in vegetal matrices. The metabolomic study allowed us to identify a new compound, named salvianolic acid W, which was isolated and characterized mainly by NMR and MS analysis. A statistical correlation of the phenolic composition with antioxidant and anti-acetylcholinesterase activities was provided.

Identification of Ellagitannins in the Unripe Fruit of Rubus Chingii Hu and Evaluation of its Potential Antidiabetic Activity

As a functional food, the unripe fruits of Rubus chingii Hu have been widely used in China for thousands of years. Twenty-five major ellagitannins (ETs) were identified from the unripe fruits, and a novel ellagitannin, chingiitannin A (1), together with four other known ETs (2-5) were isolated and identified by HPLC-QTOF-MS/MS and 2D-NMR. Chingiitannin A showed the highest α-glucosidase and α-amylase inhibitory activities (IC₅₀ 2.89 and 4.52 μM, respectively), which occurred in a reversible and noncompetitive manner. Static quenching was indicated in a fluorescence quenching assay. Molecular docking results revealed that chingiitannin A interacted with the enzymes mainly by hydrogen bonding and was bound in the allosteric site. Chingiitannin A was nontoxic, and it increased the glucose uptake in L6 myotubes. The results suggested that the unripe fruits of Rubus chingii Hu are rich sources of ETs, and chingiitannin A might be a good candidate for functional foods or antidiabetic drugs.

Auditory metabolomics, an approach to identify acute molecular effects of noise trauma

Animal-based studies have provided important insights into the structural and functional consequences of noise exposure on the cochlea. Yet, less is known about the molecular mechanisms by which noise induces cochlear damage, particularly at relatively low exposure levels. While there is ample evidence that noise exposure leads to changes in inner ear metabolism, the specific effects of noise exposure on the cochlear metabolome are poorly understood. In this study we applied liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS)-based metabolomics to analyze the effects of noise on the mouse inner ear. Mice were exposed to noise that induces temporary threshold shifts, synaptopathy and permanent hidden hearing loss. Inner ears were harvested immediately after exposure and analyzed by targeted metabolomics for the relative abundance of 220 metabolites across the major metabolic pathways in central carbon metabolism. We identified 40 metabolites differentially affected by noise. Our approach detected novel noise-modulated metabolites and pathways, as well as some already linked to noise exposure or cochlear function such as neurotransmission and oxidative stress. Furthermore, it showed that metabolic effects of noise on the inner ear depend on the intensity and duration of exposure. Collectively, our results illustrate that metabolomics provides a powerful approach for the characterization of inner ear metabolites affected by auditory trauma. This type of information could lead to the identification of drug targets and novel therapies for noise-induced hearing loss.

[Screening for hereditary tyrosinemia and genotype analysis in newborns]

OBJECTIVE

To analyze the results of screening for hereditary tyrosinemia (HT) in newborns and its clinical features and genotype.

METHODS

The HT screening was conducted among 2 188 784 newborns from November 2013 to November 2018. The tyrosine (TYR)/ succinylacetone (SA) levels were detected by tandem mass spectrometry (MS-MS). The clinical characteristics, genetic results and following up data of identified patients were analyzed.

RESULTS

The normal ranges (0.5%-95.5%) of TYR and SA were 34.5-280.0 μmol/L and 0.16-2.58 μmol/L, respectively. Three HT cases were confirmed with a detection rate of 1∶729 595. There was 1 case of tyrosinemia type Ⅰ (HTⅠ) (homozygous variations of c.455G>A in FAH gene), 1 case of tyrosinemia type Ⅱ(HTⅡ) (heterozygous variations of c.890G>T and c.408+1G>A in TAT gene), and 1 case of tyrosinemia type Ⅲ (HT Ⅲ) (homozygous variations of c.257T>C in HPD gene). The variations of c.890G>T, c.4081G>A of TAT and c.257T>C of HPD were novel. The positive predictive value of the screening was 3.4%. Case 1 (HTⅠ) with TYR and SA values of 666.9 μmol/L and 3.87 μmol/L respectively, presented cholestasis, mild elevated of liver enzyme and lactic acid, who were although fed with TYR and phenylalanine free milk, but died at 2 months of age. Case 2 (HTⅡ) with higher TYR (625.6 μmol/L) and normal SA at screening, received medical milk treatment; during the 7 months of follow-up the baby showed normal score of Bayley assessment and normal TYR without eye and skin symptoms. Case 3 (HT Ⅲ) with TYR of 1035.3 μmol/L and normal SA at screening; during the 29 months of follow-up the value of TYR fluctuated from 532.1 μmol/L to 1060.3 μmol/L due to irregular medical milk treatment, while the score of Bayley assessment was normal.

CONCLUSIONS

HT is rare in the southern Chinese population, and the gene spectrum is scattered. Early treatment with nitisinone is recommended in children with HTⅠ, otherwise the prognosis is poor; the prognosis of children with HTⅡ is good when early treated with special diet; the prognosis of children with HTⅢ needs to be determined with more data.

Occurrence and risk assessment of multiclass endocrine disrupting compounds in an urban tropical river and a proposed risk management and monitoring framework

Endocrine disrupting compounds (EDCs) are an emerging environmental concern and commonly occur as a mixture of compounds. The EDC mixture can be more toxic than any single compound. The present study analyses EDCs in surface water in the case of an urban tropical river, the Langat River, using the multiresidue analytical method of solid phase extraction and liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS). The Langat River is used as a drinking water source and is treated for Malaysian drinking water supply. A total of 14 EDCs i.e. five hormones, seven pharmaceuticals, one pesticide, and one plasticizer were detected. Caffeine was observed to be highest at 19.33 ng/L, followed by bisphenol A and diclofenac at 8.24 ng/L and 6.15 ng/L, respectively. Using a conservative risk quotient (RQ) method, EDCs were estimated for having negligible risks under acute and chronic exposure (RQ < 0.002 and RQ_mix < 0.003; RQ < 0.01), suggesting that there is currently an insignificant ecological risk related to these compounds in the Langat River riverine ecosystem. However, the presence of EDCs in surface water raises concerns about potential human exposure to EDCs via dietary intake i.e. food and drinking water supply. Although the ecological risks are considered negligible, these risks should not be neglected in terms of future prioritization and risk management. Improvements in water quality monitoring and risk assessment in water source protection are required to support a multibarrier approach to managing drinking water supply systems for safe water supply. The present study proposes a risk management and monitoring framework for EDCs to support the aforementioned multibarrier approach.

Protein Expression Analysis in Reversible Photobleached Cells of Scenedesmus vacuolatus after High Temperature Stress

We have analyzed protein expression in the bleached small vegetative cells of synchronous Scenedesmus vacuolatus to investigate how unicellular algae lived through stress. These cells were subjected to heat treatment (46.5 °C for 1h in dark condition) and then cultured under continuous illumination for 24 h. Flow cytometry analysis of the chlorophyll autofluorescence intensity of S. vacuolatus cells indicated that heat-treated cells were completely bleached within 24 h of light cultivation. Transmission electron microscopy (TEM) images showed that bleached cells maintained thylakoid membrane structure, but with lower contrast. The bleached cells regained green color after 72 h, along with a recovery in contrast, which indicated a return of photosynthetic ability. Two-dimensional gel electrophoresis (2DE) showed that the protein expression patterns were very difference between control and bleached cells. ATP synthase subunits and glutamine synthetase were down-regulated among the many differences, while some of phototransduction, stress response proteins were up-regulated in bleached cells, elucidating bleached cells can undergo changes in their biochemical activity, and activate some stress response proteins to survive the heat stress and then revive. In addition, small heat shock proteins (HSPs), but not HSP40 and HSP70 family proteins, protected the bleaching cells.

Comparative Integrated Omics Analysis of the Hfq Regulon in Bordetella pertussis

Bordetella pertussis is a Gram-negative strictly human pathogen of the respiratory tract and the etiological agent of whooping cough (pertussis). Previously, we have shown that RNA chaperone Hfq is required for virulence of B. pertussis. Furthermore, microarray analysis revealed that a large number of genes are affected by the lack of Hfq. This study represents the first attempt to characterize the Hfq regulon in bacterial pathogen using an integrative omics approach. Gene expression profiles were analyzed by RNA-seq and protein amounts in cell-associated and cell-free fractions were determined by LC-MS/MS technique. Comparative analysis of transcriptomic and proteomic data revealed solid correlation (r² = 0.4) considering the role of Hfq in post-transcriptional control of gene expression. Importantly, our study confirms and further enlightens the role of Hfq in pathogenicity of B. pertussis as it shows that Δhfq strain displays strongly impaired secretion of substrates of Type III secretion system (T3SS) and substantially reduced resistance to serum killing. On the other hand, significantly increased production of proteins implicated in transport of important metabolites and essential nutrients observed in the mutant seems to compensate for the physiological defect introduced by the deletion of the hfq gene.

Use of autoclave extraction-supercritical fluid chromatography/tandem mass spectrometry to analyze 4-(methylintrosamino)-1-(3-pyridyl)-1-butanone and N'-nitrosonornicotine in tobacco

4-(methylintrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN) are the most prevalent and toxic tobacco specific nitrosamines (TSNAs). Due to their carcinogenicity, knowledge of the composition of NNK and NNN in tobacco is necessary. Herein, a sensitive and rapid method, which employs autoclave extraction-supercritical fluid chromatography/tandem mass spectrometry (SFC-MS/MS), has been developed for the analysis of NNK and NNN in tobacco. Both water-soluble and matrix-bound NNK and NNN were extracted with 100 mM ammonium acetate in an autoclave (130 °C, 4 h), and the aqueous extract was subjected to solvent replacement prior to SFC-MS/MS analysis. NNK and NNN were effectively separated within 5 min by using supercritical CO2 as the main mobile phase coupled with a co-solvent of methanol. Excellent linearity was obtained with coefficients of determination (R2) greater than 0.9997 in the range of 1-160 ng/mL and 5-800 ng/mL for NNK and NNN, respectively. The recoveries were in the range of 92.5-110.0% at different spiked levels of real samples. 12 tobacco samples which include 3 typical tobacco varieties of burley, flue-cured, and oriental tobaccos had been analyzed, and the fraction of matrix-bound NNK was determined as well. In addition, a comparison between the proposed SFC-MS/MS method and a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) internal standard method was conducted. Both techniques exhibit comparable analysis results, but peak splitting of NNN was observed by LC-MSMS due to the existence of E/Z isomers, while SFC-MS/MS offers great improvement through elution condition optimization, demonstrating the applicability of SFC-MS/MS as an alternative tool for NNK and NNN analysis.

Sorbus domestica Leaf Extracts and Their Activity Markers: Antioxidant Potential and Synergy Effects in Scavenging Assays of Multiple Oxidants

Sorbus domestica leaves are a traditionally used herbal medicine recommended for the treatment of oxidative stress-related diseases. Dry leaf extracts (standardized by LC-MS/MS and LC-PDA) and nine model activity markers (polyphenols), were tested in scavenging assays towards six in vivo-relevant oxidants (O2•-, OH•, NO•, H2O2, ONOO-, HClO). Ascorbic acid (AA) and Trolox (TX) were used as positive standards. The most active extracts were the diethyl ether and ethyl acetate fractions with activities in the range of 3.61-20.03 µmol AA equivalents/mg, depending on the assay. Among the model compounds, flavonoids were especially effective in OH• scavenging, while flavan-3-ols were superior in O2•- quenching. The most active constituents were quercetin, (-)-epicatechin, procyanidins B2 and C1 (3.94-24.16 µmol AA/mg), but considering their content in the extracts, isoquercitrin, (-)-epicatechin and chlorogenic acid were indicated as having the greatest influence on extract activity. The analysis of the synergistic effects between those three compounds in an O2•- scavenging assay demonstrated that the combination of chlorogenic acid and isoquercitrin exerts the greatest influence. The results indicate that the extracts possess a strong and broad spectrum of antioxidant capacity and that their complex composition plays a key role, with various constituents acting complementarily and synergistically.

Prioritizing potential endocrine active high resolution mass spectrometry (HRMS) features in Minnesota lakewater

Liquid chromatography high-resolution mass spectrometry (LC-HRMS) shows great potential for expanding our understanding of relevant unknown chemical components present within complex environmental mixtures. This study identified potentially endocrine active components within Minnesota lakewater by prioritizing LC-HRMS features uniquely present at sunfish spawning habitats where male fish showed signs of estrogen agonism. Porewater samples from four locations within the same lake were analyzed using liquid chromatography quadrupole time of flight mass spectrometry (LC-QToF/MS) with positive (ESI+) and negative (ESI-) electrospray ionization. Plasma vitellogenin concentrations of captured male sunfish was used to designate sites as either endocrine active (ACT; 2 sites) or reference (REF; 2 sites). Assuming unique chemical presence at active sites contributed to endocrine activity, features at significantly higher intensities (p-value < 0.05, t-value > t-critical, log-fold change > 0.1; equal variance t-test of log2 transformed data) in ACT sites were then compiled into a suspect search list for feature identification. Adducts and isotopes of prioritized features were deprioritized using pattern recognizing algorithms using mass, retention time, and intensity. Feature identities were reported according to established confidence metrics using spectral libraries and elemental composition algorithms. This LC-HRMS approach identified a number of features omitted by targeted analysis with higher relative abundances in ACT sites, including plant essential oils, fatty acids, and mycotoxins. Multivariate analysis determined whether features were either present at both sites (AB) or unique to individual ACT sites (A or B). Detection frequency across datasets indicated bias in feature prioritization influenced by the chosen sampling method and sample acquisition mode. The majority of features prioritized by this workflow remain tentatively identified or unidentified masses of interest, reflective of current limitations in shared spectral libraries for soft ionization analyses. Strategies similar to this workflow have the potential to reduce bias in database-driven toxicological prioritization frameworks.

Development and Characterization of a Multimycotoxin Reference Material

Background: Matrix-matched reference materials (RMs) are critical for adequate quality assurance of extraction, digestion, separation, and/or detection processes for analytes of interest in foods and dietary supplements. The accurate determination of mycotoxins in foods is an international concern. While RMs for mycotoxins are available from a variety of RM producers, these mainly address a single mycotoxin or group of mycotoxins and therefore require the use of multiple RMs for multitarget methods. Objective: To address the increasing needs of laboratories moving toward LC-MS-based multimycotoxin analysis, the U.S. National Institute of Standards and Technology (NIST) collaborated with the U.S. Food and Drug Administration (FDA) to produce a naturally incurred RM for multiple mycotoxins in corn. Methods: Homogeneity of the RM has been assessed using a stratified random sampling of the final product based on mycotoxin mass fractions measured by the FDA and NIST. Multiple sample sizes were evaluated to maximize homogeneity in the obtained results. The mycotoxin levels in the final materials have been evaluated via interlaboratory comparison and isotope dilution LC-tandem MS measurements made at the FDA and NIST. The final value assignment combined results from these data sets. Conclusions: The study successfully developed a certified RM, SRM 1565 Mycotoxins in Corn, and a workflow for the future development of multimycotoxin RMs in different matrices.