Alterations of lung microbiota in lung transplant recipients with pneumocystis jirovecii pneumonia.

BACKGROUND: Increasing evidence revealed that lung microbiota dysbiosis was associated with pulmonary infection in lung transplant recipients (LTRs). Pneumocystis jirovecii (P. jirovecii) is an opportunistic fungal pathogen that frequently causes lethal pneumonia in LTRs. However, the lung microbiota in LTRs with P. jirovecii pneumonia (PJP) remains unknow. METHODS: In this prospective observational study, we performed metagenomic next-generation sequencing (mNGS) on 72 bronchoalveolar lavage fluid (BALF) samples from 61 LTRs (20 with PJP, 22 with PJC, 19 time-matched stable LTRs, and 11 from LTRs after PJP recovery). We compared the lung microbiota composition of LTRs with and without P. jirovecii, and analyzed the related clinical variables. RESULTS: BALFs collected at the episode of PJP showed a more discrete distribution with a lower species diversity, and microbiota composition differed significantly compared to P. jirovecii colonization (PJC) and control group. Human gammaherpesvirus 4, Phreatobacter oligotrophus, and Pseudomonas balearica were the differential microbiota species between the PJP and the other two groups. The network analysis revealed that most species had a positive correlation, while P. jirovecii was correlated negatively with 10 species including Acinetobacter venetianus, Pseudomonas guariconensis, Paracandidimonas soli, Acinetobacter colistiniresistens, and Castellaniella defragrans, which were enriched in the control group. The microbiota composition and diversity of BALF after PJP recovery were also different from the PJP and control groups, while the main components of the PJP recovery similar to control group. Clinical variables including age, creatinine, total protein, albumin, IgG, neutrophil, lymphocyte, CD3+CD45+, CD3+CD4+ and CD3+CD8+ T cells were deeply implicated in the alterations of lung microbiota in LTRs. CONCLUSIONS: This study suggests that LTRs with PJP had altered lung microbiota compared to PJC, control, and after recovery groups. Furthermore, lung microbiota is related to age, renal function, nutritional and immune status in LTRs.

The role of DRP1 mediated mitophagy in HT22 cells apoptosis induced by silica nanoparticles.

Silica nanoparticles (SiNPs) are widely used in the biomedical field and can enter the central nervous system through the blood-brain barrier, causing damage to hippocampal neurons. However, the specific mechanism remains unclear. In this experiment, HT22 cells were selected as the experimental model in vitro, and the survival rate of cells under the action of SiNPs was detected by MTT method, reactive oxygen species (ROS), lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and adenosine triphosphate (ATP) were tested by the kit, the ultrastructure of the cells was observed by transmission electron microscope, membrane potential (MMP), calcium ion (Ca2+) and apoptosis rate were measured by flow cytometry, and the expressions of mitochondrial functional protein, mitochondrial dynein, mitochondrial autophagy protein as well as apoptosis related protein were detected by Western blot. The results showed that cell survival rate, SOD, CAT, GSH-Px, ATP and MMP gradually decreased with the increase of SiNPs concentration, while intracellular ROS, Ca2+, LDH and apoptosis rate increased with the increase of SiNPs concentration. In total cellular proteins,the expressions of mitochondrial functional proteins VDAC and UCP2 gradually increased, the expression of mitochondrial dynamic related protein DRP1 increased while the expressions of OPA1 and Mfn2 decreased. The expressions of mitophagy related proteins PINK1, Parkin and LC3Ⅱ/LC3Ⅰ increased and P62 gradually decreased, as well as the expressions of apoptosis related proteins Apaf-1, Cleaved-Caspase-3, Caspase-3, Caspase-9, Bax and Cyt-C. In mitochondrial proteins, the expressions of mitochondrial dynamic related proteins DRP1 and p-DRP1 were increased, while the expressions of OPA1 and Mfn2 were decreased. Expressions of mitochondrial autophagy associated proteins PINK1, Parkin, LC3II/LC3I increased, P62 decreased gradually, as well as the expressions of apoptosis related proteins Cleaved-Caspase-3, Caspase-3, and Caspase-9 increased, and Cyt-C expressions decreased. To further demonstrate the role of ROS and DRP1 in HT22 cell apoptosis induced by SiNPs, we selected the ROS inhibitor N-Acetylcysteine (NAC) and Dynamin-related protein 1 (DRP1) inhibitor Mdivi-1. The experimental results indicated that the above effects were remarkably improved after the use of inhibitors, further confirming that SiNPs induce the production of ROS in cells, activate DRP1, cause excessive mitochondrial division, induce mitophagy, destroy mitochondrial function and eventually lead to apoptosis.

Multiplex polymerase spiral reaction for simultaneous detection of Salmonella typhimurium and Staphylococcus aureus.

Salmonella typhimurium (S. typhimurium) and Staphylococcus aureus (S. aureus) are common food-borne pahogens that cause food poisoning in humans. In this study, we developed a method for the simultaneous determination of S. typhimurium and S. aureus based on multiplex polymerase spiral reaction (m-PSR) and melting curve analysis. Two pairs of primers were designed specifically to target the conserved invA gene of S. typhimurium and nuc gene of S. aureus, and the nucleic acid amplification reaction was achieved under isothermal conditions in the same reaction tube for 40 min at 61 °C, melting curve analysis of the amplification product was carried out. The distinct mean melting temperature allowed simultaneous differentiation of the two target bacteria in the m-PSR assay. The limit of detection of S. typhimurium and S. aureus that could be detected simultaneously was 4.1 × 10-4 ng genomic DNA and 2 × 101 CFU/mL pure bacterial culture. Based on this method, analysis of artificially contaminated samples showed excellent sensitivity and specificity consistent with those of pure bacterial cultures. This method is rapid, simultaneous and promises to be a useful tool for the detection of food-borne pathogens in the food industry.

The role and mechanism of unfolded protein response signaling pathway in methylmercury-induced apoptosis of mouse spermatocytes germ cell-2 cells.

The study aimed to explore the role and mechanism of unfolded protein response (UPR) in methylmercury (MeHg)-induced Mouse Spermatocytes (GC-2spd[ts]) apoptosis. Methods such as MTT, flow cytometry, and Western Blot were used to evaluate the cell viability, membrane potential (MMP), reactive oxygen species (ROS), calcium ion (Ca2+ ), rate of cell apoptosis, and the expression of apoptosis-related and UPR-related protein. The results showed that with the increase of MeHg concentration, cell viability and MMP decreased, ROS, Ca2+ , rate of cell apoptosis, and the expression of apoptosis-related protein and UPR-related protein increased. To further explore the effect of ROS-induced oxidative damage on it, the ROS inhibitor N-acetyl-L-cysteine (NAC) was used. The effects of MeHg on germ cell (GC-2) cells were partially inhibited after NAC pretreatment. Our present study proved that MeHg might induce cell apoptosis by activating the UPR signaling pathway in GC-2 cells and affect normal reproductive function.

EWASdb: epigenome-wide association study database.

DNA methylation, the most intensively studied epigenetic modification, plays an important role in understanding the molecular basis of diseases. Furthermore, epigenome-wide association study (EWAS) provides a systematic approach to identify epigenetic variants underlying common diseases/phenotypes. However, there is no comprehensive database to archive the results of EWASs. To fill this gap, we developed the EWASdb, which is a part of 'The EWAS Project', to store the epigenetic association results of DNA methylation from EWASs. In its current version (v 1.0, up to July 2018), the EWASdb has curated 1319 EWASs associated with 302 diseases/phenotypes. There are three types of EWAS results curated in this database: (i) EWAS for single marker; (ii) EWAS for KEGG pathway and (iii) EWAS for GO (Gene Ontology) category. As the first comprehensive EWAS database, EWASdb has been searched or downloaded by researchers from 43 countries to date. We believe that EWASdb will become a valuable resource and significantly contribute to the epigenetic research of diseases/phenotypes and have potential clinical applications. EWASdb is freely available at http://www.ewas.org.cn/ewasdb or http://www.bioapp.org/ewasdb.

Simultaneous detection of three zoonotic pathogens based on phage display peptide and multicolor quantum dots.

With the rapid development of human's exploitation of nature and animal husbandry, zoonoses have become a major public health problem worldwide. It is necessary to establish a rapid, specific and sensitive detection method to screen several zoonotic pathogenic bacteria simultaneously. In this study, phage display technology was used to screen specific peptide of three common zoonotic pathogens, E. coli O157:H7, L. monocytogenes and B. melitensis 16 M. Then, three peptide were obtained, named E2, L4 and B4, which can identify the three pathogens respectively. Three peptide modified with biotin were synthesized and were coupled to streptavidin magnetic beads (MBs) to form peptide-MBs, which enriched the above three pathogens from the samples. Three quantum dot (QD) probes were constructed by coupling three polyclonal antibodies to different fluorescent QD surfaces (QD540, QD580 and QD630). The simultaneous detection method based on peptide-MBs and QDs multicolor fluorescent labeling was established and could detect E. coli O157:H7, L. monocytogenes and B. melitensis 16 M simultaneously. The detection method took about 100 min with the detection limits of 103, 102 and 102 CFU/mL, respectively. The detection method could be also well utilized in real samples.

A novel fluorescence method for the rapid and effective detection of Listeria monocytogenes using aptamer-conjugated magnetic nanoparticles and aggregation-induced emission dots.

Fluorescence-based assays are efficient tools for the detection of Listeria monocytogenes (L. monocytogenes). However, they are always restricted by the phenomenon of aggregation-caused quenching (ACQ). The emergence of aggregation-induced emission (AIE) materials perfectly overcomes this shortcoming. Through harnessing the AIE characteristic with magnetic enrichment, we propose an approach to achieve a promising detection method that combines an aptamer and antibody-based dual recognition units. Aptamer-coupled magnetic beads were used for the specific capture of L. monocytogenes. IgG-TPE-OH@BSA NPs were facilely synthesized through encapsulating 1-(4-hydroxyphenyl)-1,2,2-triphenylethene (TPE-OH) in bovine serum albumin (BSA) microspheres, and possessed a bright fluorescence signal due to the aggregation of TPE-OH in BSA NPs. Rabbit immunoglobulin G (IgG) antibodies were labelled on the surface. In the detection system, the fluorescence intensity of the IgG-TPE-OH@BSA NPs in the supernatant was monitored to avoid the signal interference resulting from the deposit after magnetic separation. Using our strategy, the range of detection for L. monocytogenes is 10-106 cfu mL-1, and the detection limit is as low as 10 cfu mL-1 with a good selectivity. Upon analysis of spiked samples, the recoveries ranged from 95.37% to 101.90% without any pre-enrichment.

Rapid visualized isothermal nucleic acid testing of Vibrio parahaemolyticus by polymerase spiral reaction.

The aim of this study was to develop an effective and specific visual method to rapidly detect and identify Vibrio parahaemolyticus (V. parahaemolyticus) based on the polymerase spiral reaction (PSR). The method utilized only two pairs of primers designed specifically to target the conserved tlh gene sequence of V. parahaemolyticus. Nucleic acid amplification can be achieved under isothermal conditions using DNA polymerase. The reaction could be accomplished in < 40 min with high specificity and sensitivity. The limits of detection of V. parahaemolyticus in purified genomic DNA and pure culture were 300 fg/µL and 2.4 CFU/mL per reaction, respectively, which were 100-fold more sensitive than with conventional PCR. The model food samples showed consistent specificity and sensitivity to the pure bacterial culture. With these encouraging results, it is expected that the novel, effortless and reliable isothermal nucleic acid testing assay developed in this study has potential to be applied to screening for V. parahaemolyticus in seafood samples.

Colorimetric immunoassay for rapid detection of Staphylococcus aureus based on etching-enhanced peroxidase-like catalytic activity of gold nanoparticles.

A novel colorimetric immunoassay for the detection of Staphylococcus aureus (S. aureus) based on a combination of immunomagnetic separation and signal amplification via etching-enhanced peroxidase-like catalytic activity of gold nanoparticles (AuNPs) was developed. Nanoconjugates composed of gold and iron oxide nanoparticles were synthesized and further modified with antiS. aureus immunoglobulin Y (IgY), which was used for the selective enrichment and rapid separation of target bacteria in complex matrices. AuNPs functionalized with antiS. aureus aptamer were used as an artificial enzyme which has peroxidase-like catalysis activity. Catalytic activity of AuNPs is inhibited by modifying aptamer. However, catalysis of modified AuNPs remarkably enhanced by hydrogen peroxide etching. Based on collecting unbound modified AuNPs in the supernatant and 3,3',5,5'-tetramethylbenzidine-hydrogen peroxide reporting system, the yellow color of solution decreases linearly with increasing the concentration of S. aureus ranging from 10 to 106 cfu/mL. The limit of detection is 10 cfu/mL, and total detection time is 65 min. The recoveries of the S. aureus spiked in food samples are 88.2-119.8%. Schematic illustration of colorimetric method for detection of S. aureus based on the IgY-Fe3O4/Au nanocomposites as capture probes and apt-AuNPs as artificial enzyme with etching-enhanced peroxidase-like catalytic activity.

Paper chip-based colorimetric assay for detection of Salmonella typhimurium by combining aptamer-modified Fe3O4@Ag nanoprobes and urease activity inhibition.

A rapid and sensitive colorimetric assay is described for Salmonella typhimurium (S. typhimurium) detection using urea/phenol red impregnated test paper. Aptamer-modified Fe3O4@Ag multifunctional hybrid nanoprobes (apt-Fe3O4@Ag NPs) were used to specifically captured S. typhimurium; the nanoprobes were quickly etched by H2O2 to form Ag+. The generated Ag+ can inhibit the urease-catalyzed hydrolysis reaction of urea to produce NH4+. Consequently, the as-prepared test paper displayed a yellow color. In the presence of S. typhimurium, the target bacteria can cause aggregation of apt-Fe3O4@Ag NPs, and the deposited Ag on the nanoprobe's surface is shielded against H2O2-induced oxidative decomposition leading to reduced Ag+ production. The catalytic activity of urease cannot be inhibited completely by inadequate amount of Ag+. An obvious color change from yellow to pink can be monitored directly using our test paper as a result of increased NH4+. The entire assay procedure could be completed within 1 h. A limit of detection of 48 cfu/mL is achieved with a linear range of 1 × 102 to 1 × 106 cfu/mL. The recoveries of S. typhimurium spiked in pure milk samples were 92.48-94.05%. Graphical abstract Schematic diagram of the proposed colorimetric assay for S. typhimurium detection based on etching of bifunctional apt-Fe3O4@Ag NPs and inhibiting catalytic activity of urease by Ag+. A color change from yellow to pink can be observed and correlated to the concentration of S. typhimurium.

EWAS: epigenome-wide association study software 2.0.

Motivation: With the development of biotechnology, DNA methylation data showed exponential growth. Epigenome-wide association study (EWAS) provide a systematic approach to uncovering epigenetic variants underlying common diseases/phenotypes. But the EWAS software has lagged behind compared with genome-wide association study (GWAS). To meet the requirements of users, we developed a convenient and useful software, EWAS2.0. Results: EWAS2.0 can analyze EWAS data and identify the association between epigenetic variations and disease/phenotype. On the basis of EWAS1.0, we have added more distinctive features. EWAS2.0 software was developed based on our 'population epigenetic framework' and can perform: (i) epigenome-wide single marker association study; (ii) epigenome-wide methylation haplotype (meplotype) association study and (iii) epigenome-wide association meta-analysis. Users can use EWAS2.0 to execute chi-square test, t-test, linear regression analysis, logistic regression analysis, identify the association between epi-alleles, identify the methylation disequilibrium (MD) blocks, calculate the MD coefficient, the frequency of meplotype and Pearson's correlation coefficients and carry out meta-analysis and so on. Finally, we expect EWAS2.0 to become a popular software and be widely used in epigenome-wide associated studies in the future. Availability and implementation: The EWAS software is freely available at http://www.ewas.org.cn or http://www.bioapp.org/ewas.

A novel visual-mixed-dye for LAMP and its application in the detection of foodborne pathogens.

Loop-mediated isothermal amplification (LAMP) has been widely applied for the detection of foodborne pathogens. Obtaining a simple, accurate readout of LAMP reaction results is crucial. Herein, a visual-mixed-dye (VMD) containing calcein (precombined with MnCl2) and hydroxynaphthol blue (HNB) for LAMP end-point detection was developed. The optimal final concentrations of these components in VMD were 25 and 300 µM, respectively. Due to the formation of HNBMn2+ during the LAMP reaction, the VMD-loaded assay exhibited superior visual properties, changing from light gray (negative) to dark blue (positive) under natural light. Additionally, compared with traditional single calcein or HNB dye, a weakly positive result with the VMD was purple, making it easier to distinguish by the naked eye. The visual sensitivity reached down to 20.9 copies/µL, which was comparable to that based on fluorescence. In food-contaminated samples, the practicality of VMD was verified by Vibrio parahaemolyticus and Staphylococcus aureus detection with excellent specificity. Moreover, the VMD was stable over a period of 3 months. Collectively, these findings establish the VMD as a novel dye for LAMP.

Preparation and identification of chicken egg yolk immunoglobulins against human enterovirus 71 for diagnosis of hand-foot-and-mouth disease.

Human enterovirus 71 (EV71) is one of the major pathogens that causes hand-foot-and mouth disease, and there is an urgent need for rapid diagnosis of EV71 virus infection for early antiviral treatment. The aim of this study was to prepare chicken egg yolk immunoglobulin Y (IgY) for the diagnosis of enterovirus type 71 infection. The antibodies were raised by intramuscular immunization of laying hens with inactivated human EV71 and isolated from the egg yolk by multiple steps of polyethylene glycol 6000 extraction. The average concentration of IgY antibody was 26.60 mg/mL during the whole immunization. After the first immunization, the IgY titer gradually increased, and reached the peak on the 55th days. Meanwhile, the use of western blotting test demonstrated that specific IgY binds specifically to capsid proteins VP2 and VP3 of EV71 virus. Furthermore, a facile one-step method based on turn-on fluorescence sensing was developed by using IgY antibodies, which can detect EV71 virus at low concentrations of 104 PFU/mL and was 94.44% coincidence with RT-PCR in 30 clinical samples. These findings indicate that EV71-IgY antibodies are an easily prepared and rich source of antibodies that offers a potential alternative strategy for routine screening of EV71 infection.

Fluorescence signal amplification assay for the detection of B. melitensis 16M, based on peptide-mediated magnetic separation technology and a AuNP-mediated bio-barcode assembled by quantum dot technology.

Members of the Brucella spp. are facultative intracellular bacteria that can cause global brucellosis, a zoonotic disease. Herein, a novel fluorescence signal amplification (FSA) method for the rapid detection of B. melitensis 16M was developed based on peptide-mediated magnetic separation (PMS) technology and Au nanoparticle (AuNP)-mediated bio-barcode assay technology assembled by quantum dots (QDs). The PMS technology was used to specifically capture and isolate B. melitensis 16M from food. The immunomagnetic bead-B. melitensis 16M bioconjugates (IMBs-B. melitensis 16M) were then identified by IgY on the surface of AuNPs and the oligonucleotide chains on the surface of the gold nanoparticles were hybridized with bio-barcodes assembled by quantum dots (QD-probe2). The IMB/B. melitensis 16M/IgY-AuNP-probe1/QD-probe2 bioconjugates were concentrated by magnetic separation. Therefore, as the concentration of B. melitensis 16M in the sample increased, the unbound QD-probe2 in the supernatant reduced, and the B. melitensis 16M in the sample could be indirectly measured by detecting the fluorescence in the supernatant. This FSA method can detect B. melitensis 16M concentration in the range of 10 to 106 cfu ml-1 without pre-enrichment, and the limit of detection (LOD) is as low as 10 cfu ml-1 with high specificity. Furthermore, the proposed method for the detection of B. melitensis 16M has a LOD of 1.07 × 102 cfu ml-1 and a linear range from 102 to 107 cfu ml-1 in milk, and a LOD of 1.72 × 102 cfu ml-1, and a linear range from 102 to 106 cfu ml-1 in lamb leach. In addition, this method takes less than 3 h to perform. Thus, the assay that was developed in this study shows promise for rapid, sensitive, and specific detection of B. melitensis 16M.

Epidemiological characteristics of injury mortality in Guangdong Province, China, 2015.

BACKGROUND: As the fourth leading cause of death, injury is an important public health concern in Guangdong Province, China. The epidemiological characteristics of injury mortality is changing along with the social development. This study described the epidemiological characteristics of injury mortality in Guangdong Province by analyzing the death surveillance data in a few areas in Guangdong Province in 2015. METHODS: Using the mortality data from the Disease Surveillance Points (DSP) system, injury deaths were classified according to the International Classification of Disease-10th Revision (ICD-10). The data were stratified by areas (urban/rural), gender, age groups, injury types, and then overall and type-specific injury mortality rates were estimated for the whole Guangdong Province, China. RESULTS: We estimated that about 38,200 individuals died from injury in Guangdong Province in 2015, producing a mortality rate of 43.11/100,000. The overall age-standardized injury mortality in men was higher in rural areas compared with urban areas (41.29/100,000 versus 24.89/100,000). In terms of injury intent, unintentional injuries were the commonnest injury type, which accounted for 83.93% of the overall injury deaths, however, the deaths caused by suicide should not be ignored, which occupied 12.67% of the total injury deaths. In terms of injury cause type, falls, road-traffic accidents, suicide, drowning, and accidental poisoning were the top five leading types of injury deaths. CONCLUSIONS: In Guangdong Province, injury is an important cause of death. Road-traffic accidents, falls, suicide, drowning, and accidental poisoning should be the priorities of intervention. Moreover, in rural areas, the men were the most targeted subpopulation of the prevention activities.

Colorimetric detection of Staphylococcus aureus using gold nanorods labeled with yolk immunoglobulin and urease, magnetic beads, and a phenolphthalein impregnated test paper.

A colorimetric test is described for the rapid detection of Staphylococcus aureus (SA). Gold nanorods (AuNRs) are first labeled with urease and yolk immunoglobulin (IgY). This probe can specifically bind SA. In the next step, nonspecific magnetic beads and sample are added. This leads to the formation of the AuNR-IgY-SA-nMB immunocomplex which is then magnetically separated. Finally, a solution of urea is added to the supernatant. Ureases catalyzes the decomposition of urea which results in an increase in the pH value. The increase in the pH value is detected by using a phenolphthalein test paper which undergoes a color change from white to pink. The analytical process can be completed within 20 min. The method is highly specific and can detect as little as 476 cfu·mL-1. It was verified by analyzing contaminated Chinese cabbage and beef samples, and 1000 cfu·mL-1 of SA were accurately detected. Graphical abstract Schematic representation of a colorimetric method for the detection of Staphylococcus aureus based on the immunocomplex formed from dual-labeled gold nanorod (AuNR) probe, bacteria and non-specific magnetic bead (nMB). This method can be completed within 20 min.

A cross-sectional survey based on blood VOCs, hematological parameters and urine indicators in a population in Jilin, Northeast China.

The objective of this study was to examine whether long-term exposure to low-dose volatile organic compounds (VOCs) will have an effect on the health of non-occupational population. A total of 499 non-occupational participants aged more than 18 that live around Jilin Petrochemical Industrial Zone were chosen by stratified cluster random sampling. Their blood VOCs' levels, hematological parameters and urine indicators together with detailed questionnaire data were used to find possible relationships using binary logistic regression analysis. The detection rate of benzene in the blood was high in the non-occupational population around the industrial area, and it even reached 82.3% in males but no significant difference was recorded between male and female population. In addition, trichloroethane (male: 33.2% V female: 21.7%; p = 0.002), carbon tetrachloride (males: 20.3% V females: 7.5%; p < 0.001) and trichlorethylene (male: 34.9% V female: 24.7%; p = 0.004) all showed significant differences in gender, and without exception, the prevalence of males was higher in these three VOCs than of females. The changes in red blood cell (RBC), hematocrit (HCT) and basophils are correlated with carbon tetrachloride, trichloroethylene and chloroform, respectively. And RBC, HCT and basophils are statistically significant in male compared with female of the study population. The increase in trichlorethylene was associated with an increase of 1.723% (95% CI 1.058-2.806) in HCT. The increase in carbon tetrachloride showed a more significant correlation with an increase of 2.638% in RBC count (95% CI 1.169-5.953). And trichloromethane led to a 1.922% (95% CI 1.051-3.513) increase in basophils. The changes in urinary WBC, urine ketone (KET) and urinary bilirubin (BIL) showed significant correlation with benzene, carbon tetrachloride and dibromochloromethane, respectively. The correlation in females is more significant than in males. The increase of benzene in the female population increased urinary leukocyte count by 2.902% (95% CI 1.275-6.601). The effect of carbon tetrachloride on KET was particularly pronounced, resulting in an increase of 7.000% (95% CI 1.608-30.465). Simultaneously, an increase in dibromochloromethane caused an increase of 4.256% (95% CI 1.373-13.192) in BIL. The changes in RBC, HCT and basophils can only serve as an auxiliary indicator for disease diagnosis, so they have no significant clinical significance. However, the alteration of urinary WBC, KET and BIL has great clinical significances, and it is suggested that the monitoring of the above indicators from low-dose long-term exposure be strengthen in this area.

Development of a low-cost paper-based ELISA method for rapid Escherichia coli O157:H7 detection.

Escherichia coli O157: H7 (E. coli O157: H7) has become one of the most dangerous foodborne pathogenic bacteria around the world. Currently, because of the tedious, high-cost and stringent laboratory conditions required, the conventional E. coli O157: H7 detection methods, such as culture-based methods and polymerase chain reaction (PCR), have much limitation. Thus, we developed a novel paper-based enzyme-linked immunosorbent assay (p-ELISA) with shorter operation duration, lower cost, relatively higher sensitivity and wider application. This method required less than 3 h and 5 µL of sample to complete the detection. The limit of detection (LOD) for E. coli O157: H7 reached 1 × 104 CFU/mL with high specificity. To be more suitable for on-site testing, the readout could be rapidly obtained without any expensive instruments. In this study, we chose E. coli O157:H7 as the representative, and our method could provide a platform for determination of other pathogenic bacteria.

Colorimetric immunoassay for Listeria monocytogenes by using core gold nanoparticles, silver nanoclusters as oxidase mimetics, and aptamer-conjugated magnetic nanoparticles.

The authors describe a rapid colorimetric assay for Listeria monocytogenes (L. monocytogenes) based on the o-phenylenediamine-mediated deaggregation of gold nanoparticles. Silver nanoclusters are used as an artificial enzyme that can oxidize o-phenylenediamine to form o-benzoquinone diamine. Aptamer and IgY antibodies were chosen to conjugate with magnetic beads and silver nanoclusters, respectively, which can recognize and bind L. monocytogenes at different specific binding sites. This results in the disassembly of colloidal gold nanoparticles which is accompanied by a color change from blue to red, with peaks at 730 and 525 nm, respectively. The method allows L. monocytogenes to be colorimetrically determined in the 10 to 106 cfu·mL-1 concentration range without pre-enrichment, and the limit of detection is as low as 10 cfu·mL-1. Recoveries ranging from 97.4 to 101.3% are found when analyzing spiked food samples. The assay is rapid, sensitive and specific. Graphical abstract Schematic illustration of a colorimetric method for detection of L. monocytogenes based on silver nanoclusters-catalyzed oxidation of OPD and de-aggregation of GNPs. A color change from blue to red can be observed and correlated to the concentration of L. monocytogenes.

A novel multi-epitope recombined protein for diagnosis of human brucellosis.

BACKGROUND: In epidemic regions of the world, brucellosis is a reemerging zoonosis with minimal mortality but is a serious public hygiene problem. Currently, there are various methods for brucellosis diagnosis, however few of them are available to be used to diagnose, especially for serious cross-reaction with other bacteria. METHOD: To overcome this disadvantage, we explored a novel multi-epitope recombinant protein as human brucellosis diagnostic antigen. We established an indirect enzyme-linked immunosorbent assay (ELISA) based on this recombinant protein. 248 sera obtained from three different groups including patients with brucellosis (146 samples), non-brucellosis patients (82 samples), and healthy individuals (20 samples) were tested by indirect ELISA. To evaluate the assay, a receiver-operating characteristic (ROC) analysis and immunoblotting were carried out using these characterized serum samples. RESULTS: For this test, the area under the ROC curve was 0.9409 (95 % confidence interval, 0.9108 to 0.9709), and a sensitivity of 88.89 % and a specificity of 85.54 % was given with a cutoff value of 0.3865 from this ROC analysis. The Western blot results indicate that it is feasible to differentiate human brucellosis and non-brucellosis with the newly established method based on this recombinant protein. CONCLUSION: Our results obtained high diagnostic accuracy of the ELISA assay which encourage the use of this novel recombinant protein as diagnostic antigen to implement serological diagnosis of brucellosis.