A study for quality evaluation of Taxilli Herba from different hosts based on fingerprint-activity relationship modeling and multivariate statistical analysis

In this study, a fingerprint-activity relationship modeling between chemical fingerprints and antirheumatic activity was established, and multivariate statistical analysis was used to evaluate the quality of Taxilli Herba (TH) from different hosts. Characteristic fingerprints of 20 batches of TH samples were generated by high-performance liquid chromatography coupled with triple quadrupole-time of flight tandem mass spectrometry (HPLC-Triple TOF-MS/MS), and the similarity analysis was calculated based on thirteen common characteristic peaks by hierarchical clustering analysis (HCA). Subsequently, nine efficacy markers were discovered by combining fingerprints and antirheumatic activity through grey correlation analysis (GCA) and bivariate correlation analysis (BCA). Meanwhile, the content of 5 constituents in 9 markers was determined by high-performance liquid chromatography coupled with triple quadrupole-linear ion trap tandem mass spectrometry (HPLC-QTRAP-MS/MS). The comprehensive quality of TH was assessed using multivariate statistical analysis, including principal components analysis (PCA) and technique for order preference by similarity to ideal solution (TOPSIS). The results showed that a high dose of TH extract could markedly ameliorate arthritis damage compared to other doses, with flavonoids playing an important role in the antirheumatic activity. The comprehensive quality of samples from Morus alba L. (SS) was superior to those from Liquidambar formosana Hance (FXS). The present study will demonstrate the markers associated with efficacy, and provide an applicable strategy for more comprehensive quality control and evaluation of TH.     

A surface plasmon resonance biosensor for detecting Pseudomonas aeruginosa cells with self-assembled chitosan-alginate multilayers

A self-assembled multilayer (SAMu) including the alginate layer was prepared for detecting Pseudomonas aeruginosa cells in a solution and its potential was evaluated with a BIAcore system. After layer-by-layer formation, the refractive units (RU) values monitored with the biosensor increased by the interaction between the layers. The responses by the binding of P. aeruginosa cells to the alginate-immobilized SAMu were visualized immediately upon injection of the cell suspension. The RU values after injection of the cells were measured with approximately 1152, 656 and 173 for 1 × 10⁹, 1 × 10⁸ and 1 × 10⁷ CFU/ml. This result suggests that the alginate-immobilized SAMu will have useful application for detecting P. aeruginosa cells in a biosensor analysis.     

毛竹慢性枯萎病病原鉴定

连续3年调查发生慢性枯萎病不同发病程度的毛竹,进行了病原的分离、纯化及鉴定。结果表明,毛竹慢性枯萎病的病原菌是一种粘帚霉(Gliocladiumsp.)。该菌初生分生孢子梗轮枝状,长96~128μm,顶端轮生4~5个细瓶形小梗,轮生小梗长约19.2~24μm;次生分生孢子梗青霉状,长64~128μm,瓶梗大小(4.0~4.8)μm×(6.4~9.6)μm;分生孢子大小(2.4~6.2)μm×(1.9~3.2)μm。     

Precise characterization method of antibody‐conjugated magnetic nanoparticles for pathogen detection using stuffer‐free multiplex ligation‐dependent probe amplification

Antibody‐conjugated magnetic nanoparticles (Ab‐MNPs) have potential in pathogen detection because they allow target cells to be easily separated from complex sample matrices. However, the sensitivity and specificity of pathogen capture by Ab‐MNPs generally vary according to the types of MNPs, antibodies, and sample matrices, as well as preparation methods, including immobilization. Therefore, achieving a reproducible analysis utilizing Ab‐MNPs as a pathogen detection method requires accurate characterization of Ab‐MNP capture ability and standardization of all handling processes. In this study, we used high‐resolution CE‐single strand conformational polymorphism coupled with a stuffer‐free multiplex ligation‐dependent probe amplification system to characterize Ab‐MNPs. The capture ability of Ab‐MNPs targeting Salmonella enteritidis and nine pathogens, including S. enteritidis, was analyzed in phosphate buffer and milk. The effect of storage conditions on the stability of Ab‐MNPs was also assessed. The results showed that the stuffer‐free multiplex ligation‐dependent probe amplification system has the potential to serve as a standard characterization method for Ab‐MNPs. Moreover, the precise characterization of Ab‐MNPs facilitated robust pathogen detection in various applications.     

Rapid and sensitive detection of lower respiratory tract infections by stuffer‐free multiplex ligation‐dependent probe amplification

Lower respiratory tract infection is one of the most common infectious diseases. However, conventional methods for detecting infectious pathogens are time‐consuming, and generally have a limited impact on early therapeutic decisions. We previously reported a rapid and sensitive method for detecting such pathogens using stuffer‐free multiplex ligation‐dependent probe amplification coupled with high‐resolution CE‐SSCP. In this study, we report an application of this method to the detection of respiratory pathogens. As originally configured, this method was capable of simultaneously detecting seven bacterial species responsible for lower respiratory tract infections, but its detection limit and assay time were insufficient to provide useful information for early therapeutic decisions. To improve sensitivity and shorten assay time, we added a target‐specific preamplification step, improving the detection limit from 50 pg of genomic DNA to 500 fg. We further decreased time requirements by optimizing the hybridization step, enabling the entire assay to be completed within 7 h while maintaining the same detection limit. Taken together, these improvements enable the rapid detection of infectious doses of pathogens (i.e. a few dozen cells), establishing the strong potential of the refined method, particularly for aiding early treatment decisions.     

Simultaneous analysis of multiple PCR amplicons enhances capillary SSCP discrimination of MHC alleles

Major histocompatibility complex (MHC) genotyping still remains one of the most challenging issues for evolutionary ecologists. To date, none of the proposed methods have proven to be perfect, and all provide both important pros and cons. Although denaturing capillary electrophoresis has become a popular alternative, allele identification commonly relies upon conformational polymorphisms of two single‐stranded DNA molecules at the most. Using the MHC class II (β chain, exon 2) of the black kite (Aves: Accipitridae) as our model system, we show that the simultaneous analysis of overlapping PCR amplicons from the same target region substantially enhances allele discrimination. To cover this aim, we designed a multiplex PCR capable to generate four differentially sized and labeled amplicons from the same allele. Informative peaks to assist allele calling then fourfold those generated by the analysis of single PCR amplicons. Our approach proved successful to differentiate all the alleles (N=13) isolated from eight unrelated birds at a single optimal run temperature and electrophoretic conditions. In particular, we emphasize that this approach may constitute a straightforward and cost‐effective alternative for the genotyping of single or duplicated MHC genes displaying low to moderate sets of divergent alleles.     

Bioactive paper provides a low-cost platform for diagnostics

Bioactive paper includes a range of potential paper-based materials that can perform analytical functions normally reserved for multi-well plates in the laboratory or for portable electronic devices. Pathogen detection is the most compelling application. Simple paper-based detection, not requiring hardware, has the potential to have impacts in society, ranging from the kitchen to disasters in the developing world. Bioactive-paper research is an emerging field with significant efforts in Canada, USA (Harvard), Finland and Australia.Following a brief introduction to the material and surface properties of paper, I review the literature. Some of the early work exploits the porosity of paper to generate paper-based microfluidics (“paperfluidics”) devices. I exclude from this review printed electronic devices and plastics-supported devices.     

病原微生物感染的蛋白质组学研究

基于质谱的蛋白质组学在近20年有巨大的发展。在其应用中,病原微生物和与感染相关的蛋白质组学具有重要科学意义,体系复杂度又相对较小,一直受到广泛关注并有较快发展。本文从感染中病原微生物和宿主的蛋白质组学两方面入手,简要综述应用蛋白质组学研究感染过程的相关工作,着重介绍该领域近几年的主要进展,并对其发展做出展望。     

The classification for dynamics of an STD model

In this paper, a 3(n+1) dimensional sexually transmitted disease model is studied. The model involves two competing strains 1 and 2, where females are divided into n different groups based on their susceptibility to two distinct pathogenic strains. The first and second reproduction numbers , which have their biological meaning, are defined for strain , respectively. With the non-degeneracy assumption (H), a complete classification for dynamics of this model in terms of is presented, which is based on the theory of type-K monotone dynamical systems.     

A fully portable microchip real‐time polymerase chain reaction for rapid detection of pathogen

Point‐of‐care detection for pathogen is of critical need for wide epidemic warning and medical diagnosis. In this work, we have designed and developed a fully portable and integrated microchip based real‐time polymerase chain reaction machine for rapid pathogen detection. The instrument consists of three functional components including heating, optical, and electrical modules, which are integrated into a portable compact box. The microchip is consumable material replaceable to meet various detection needs. Consequently, we demonstrated the outstanding performance of this portable machine for rapid detection of Salmonella and Escherichia coli O157:H7 with the advantage of time‐saving (～25 min), less samples consumption, portability, and user‐friendly operation.