Rapid detection of lactobacillus and yeast concentrations using a particle size distribution analyser

Kim, H.,Park, K.,Oh, S.,Chang, I.S. Blackwell Publishing Ltd 2009 Journal of applied microbiology Vol.107 No.5

<P>Abstract</P><P>Aims: </P><P>To see the possibility of particle size distribution analyser (PSDA) in detecting concentration of lactobacillus contaminants in yeast fermentation.</P><P>Methods and Results: </P><P>A PSDA was used to rapidly determine the size and concentration of lactobacillus and <I>Saccharomyces cerevisiae</I>. Data showed that the aerodynamic diameters of <I>Lactobacillus casei</I> and <I>S. cerevisiae</I> cells were around 0·63 and 2·9 &mgr;m, respectively, with both cultures showing a linear relationship between cell density and particle count on a size distribution curve of PSDA. In addition, <I>Lactobacillus fermentum</I> showed high similarity in bacterial size distribution and particle count numbers with <I>L. casei</I>. The PSDA also rapidly detected (within 1 min) the cell concentrations of <I>S. cerevisiae</I> and <I>L. casei</I> in a mixed sample with different concentration ratios with 10<SUP>7</SUP>–10<SUP>9</SUP> cells ml<SUP>−1</SUP> of detection range.</P><P>Conclusions: </P><P>PSDA was demonstrated to be useful for the rapid detection of lactobacillus and <I>S. cerevisiae</I> concentrations.</P><P>Significance and Impact of the Study: </P><P>This is the first report concerning PSDA to detect the concentration of bacteria and yeast. This method can be useful in the actual field during ethanol fermentation because of relatively easy handling and rapid detection.</P>

Optimized Expression, Purification, and Rapid Detection of Recombinant Influenza Nucleoproteins Expressed in Sf9 Insect Cells

( Sung-jin Yoon ),( Young-jun Park ),( Hyun Ju Kim ),( Jinwoo Jang ),( Sang Jun Lee ),( Sunwoo Koo ),( Moo-seung Lee ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.10

Accurate and rapid diagnosis of influenza infection is essential to enable early antiviral treatment and reduce the mortality associated with seasonal and epidemic infections. Immunochromatography is one of the most common methods used for the diagnosis of seasonal human influenza; however, it is less effective in diagnosing pandemic influenza virus. Currently, rapid diagnostic kits for pandemic influenza virus rely on the detection of nucleoprotein (NP) or hemagglutinin (HA). NP detection shows higher specificity and is more sensitive than HA detection. In this study, we time-dependently screened expression conditions, and herein report optimal conditions for the expression of recombinant nucleoprotein (rNP), which was 48 h after infection. In addition, we report the use of the expressed rNP in a rapid influenza diagnostic test (SGT i-flex Influenza A&B Test). We constructed expression vectors that synthesized rNP (antigen) of influenza A and B in insect cells (Sf9 cells), employed the purified rNP to the immunoassay test kit, and clearly distinguished NPs of influenza A and influenza B using this rapid influenza diagnostic kit. This approach may improve the development of rapid test kits for influenza using NP.

Rapid Detection of Clostridium tetani by Recombinase Polymerase Amplification Using an Exo Probe

( Mingjing Guo ),( Pan Feng ),( Liqun Zhang ),( Chunfeng Feng ),( Jie Fu ),( Xiaoyun Pu ),( Fei Liu ) 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.1

Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.

One-Class Convolutional Neural Network (OC-CNN) Model for Rapid Bridge Damage Detection Using Bridge Response Data

Fadel Yessoufou,Jinsong Zhu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

This study proposes a numerical investigation for rapid bridge damage detection based on a semi-supervised deep learning (DL) model and a damage index (DI)-based Gaussian process. The proposed damage detection method uses bridge response data (acceleration and displacement data) from various damage scenarios within a simply supported girder bridge subjected to a two-axle moving vehicle load. As for semi-supervised learning, we used a one-class convolutional neural network (OC-CNN) model. This model combines a one-class (OC) classification algorithm with a simple one-dimensional convolutional neural network (1D CNN) configuration. The performance of the proposed OC-CNN model was evaluated through a numerical example of a vehicle-bridge coupling system. The proposed OC-CNN model trained using acceleration data showed promising results for different vehicle weights and speeds. These results offer confidence in using the prediction error loss of the proposed OC-CNN model as an ideal damage-sensitive feature for rapid bridge damage detection. In addition, the Gaussian process used in the DI can classify the prediction error losses resulting from the change induced by different damage severities (10%, 20%, and 30%) and different types of damage scenarios (single damage, double damages, and multiple damages). These results emphasize the potential of the proposed damage detection method to monitor the state of bridges in practical engineering.

Rapid Detection of Salmonella Typhimurium and Escherichia coli using Surface-Enhanced Raman Spectroscopy

박미경,박민서 경상대학교 농업생명과학연구원 2014 농업생명과학연구 Vol.48 No.5

The potential application of surface-enhanced Raman spectroscopy (SERS) was investigated todetect Salmonella Typhimurium and Escherichia coli. The silver colloidal suspension withoptimum optical characteristics was obtained for SERS detection. The SERS spectra werecollected the wavelengths from 500 to 1200 cm-1. The characteristic SERS spectra were obtainedfrom both S. Typhimurium and E. coli; however the observed SERS peak profiles for bothpathogens exhibited similar peak profiles. Therefore, the results suggest that even though SERSpossesses the potential capability to detect pathogens rapidly, further study is required to resolvethe ambiguous spectra profiles for S. Typhimurium and E. coli.

Trends in the rapid detection of infective oral diseases

Ran-Yi Jin,Han-gyoul Cho,Seung-Ho Ohk 대한구강생물학회 2023 International Journal of Oral Biology Vol.48 No.2

The rapid detection of bacteria in the oral cavity, its species identification, and bacterial count determination are important to diagnose oral diseases caused by pathogenic bacteria. The existing clinical microbial diagnosis methods are time-consuming as they involve observing patients’ samples under a microscope or culturing and confirming bacteria using polymerase chain reaction (PCR) kits, making the process complex. Therefore, it is required to analyze the development status of substances and systems that can rapidly detect and analyze pathogenic microorganisms in the oral cavity. With research advancements, a close relationship between oral and systemic diseases has been identified, making it crucial to identify the changes in the oral cavity bacterial composition. Additionally, an early and accurate diagnosis is essential for better prognosis in periodontal disease. However, most periodontal diseasecausing pathogens are anaerobic bacteria, which are difficult to identify using conventional bacterial culture methods. Further, the existing PCR method takes a long time to detect and involves complicated stages. Therefore, to address these challenges, the concept of point-of-care (PoC) has emerged, leading to the study and implementation of various chair-side test methods. This study aims to investigate the different PoC diagnostic methods introduced thus far for identifying pathogenic microorganisms in the oral cavity. These are classified into three categories: 1) microbiological tests, 2) microchemical tests, and 3) genetic tests. The microbiological tests are used to determine the presence or absence of representative causative bacteria of periodontal diseases, such as A. actinomycetemcomitans , P. gingivalis , P. intermedia , and T. denticola . However, the quantitative analysis remains impossible, and detecting pathogens other than the specific ones is challenging. The microchemical tests determine the activity of inflammation or disease by measuring the levels of biomarkers present in the oral cavity. Although this diagnostic method is based on increase in the specific biomarkers proportional to inflammation or disease progression in the oral cavity, its commercialization is limited due to low sensitivity and specificity. The genetic tests are based on the concept that differences in disease vulnerability and treatment response are caused by the patient’s DNA predisposition. Specifically, the IL-1 gene is used in such tests. PoC diagnostic methods developed to date serve as supplementary diagnostic methods and tools for patient education, in addition to existing diagnostic methods, although they have limitations in diagnosing oral diseases alone. Research on various PoC test methods that can analyze and manage the oral cavity bacterial composition is expected to become more active, aligning with the shift from treatmentoriented to prevention-oriented approaches in healthcare.

Shell Vial 방법을 이용한 임상가검물에 대한 인형거대세포 바이러스의 조기 검색

김유경,김은순,조영걸,송재훈 대한바이러스학회 1995 Journal of Bacteriology and Virology Vol.25 No.1

A rapid detection method was developed and applied for the detection of cytomegalovirus (CMV) antigen from various clinical specimens. The shell vial culture method allowed to replicate low titer of virus present in clinical specimens in cell culture, and subsequent immunofluorescence staining of the infected MRC-5 cell monolayers detected CMV antigen. Eighty-four blood specimens, 82 urine specimens, 35 bronchoalveolar lavage (BAL) specimens, and 9 other specimens, were examined for the presence of CMV by the method. Twenty-eight episodes of CMV infection were detected: 4 from blood specimens, 16 from urine specimens, 6 from BAL specimens, and 2 from other specimens. Most of antigen-positive patients were those receiving organ transplants. The shell vial culture method is a simple and rapid method for detecting CMV antigen from clinical specimens. The method can be applied to other medically important viruses.

육회와 육사시미에 접종된 Salmonella Typhimurium와 Listeria monocytogenes 검출을 위한 Loop-mediated isothermal amplification와 식품공전의 배지 시험법, real-time PCR의 검출 성능 비교

곽승해,이소영,김진희,오세욱 한국식품위생안전성학회 2019 한국식품위생안전성학회지 Vol.34 No.3

The object of this study is to compare the performance of the 3M Molecular Detection Assay 2 (3M MDA 2) and the Korea Standard Food Codex (KSFC) Method (i.e., isolation media and real-time PCR) in detect-ing Salmonella Typhimurium and Listeria monocytogenes in traditional Korean foods. Yuk-hwe and Yuk-sashimi (types of raw beef dishes) were artificially inoculated with 100–104 CFU/25 g of L. monocytogenes and S. Typh-imurium. Citrobacter freundii and Listeria innocua were used as competitive microflora. After enrichment, the sam-ples were analyzed using 3M MDA 2 and real-time PCR. All samples inoculated at concentrations of 100–104 CFU/ 25 g without competitive microflora were positive for S. Typhimurium and L. monocytogenes, as detected by 3M MDA 2 and Korea Standard Food Codex (KFSC) Method. In addition, part of the samples were positive for the pres-ence of C. freundii and L. innocua. The 3M MDA 2 – Salmonella and Korea Standard Food Codex (KFSC) Method showed similar detection performances in Yuk-hwe and Yuk-sashimi. The 3M MDA 2 method for Salmonella and Listeria, which is a LAMP-based technology, can be used for rapid detection of S. Typhimurium and L. monocyto-genes in raw beef. LAMP bioluminescence assays provide results on the subsequent day and are simple to use com-pared with the Korea Standard Food Codex (KFSC) Method, particularly in terms of DNA preparation.

Development of Enzymatic Recombinase Amplification Assays for the Rapid Visual Detection of HPV16/18

Ding Ning,Qi Wanwan,Wu Zihan,Zhang Yaqin,Xu Ruowei,Lin Qiannan,Zhu Jin,Zhang Huilin 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.8

Human papillomavirus (HPV) types 16 and 18 are the major causes of cervical lesions and are associated with 71% of cervical cancer cases globally. However, public health infrastructures to support cervical cancer screening may be unavailable to women in low-resource areas. Therefore, sensitive, convenient, and cost-efficient diagnostic methods are required for the detection of HPV16/18. Here, we designed two novel methods, real-time ERA and ERA-LFD, based on enzymatic recombinase amplification (ERA) for quick point-of-care identification of the HPV E6/E7 genes. The entire detection process could be completed within 25 min at a constant low temperature (35–43°C), and the results of the combined methods could be present as the amplification curves or the bands presented on dipsticks and directly interpreted with the naked eye. The ERA assays evaluated using standard plasmids carrying the E6/E7 genes and clinical samples exhibited excellent specificity, as no cross-reaction with other common HPV types was observed. The detection limits of our ERA assays were 100 and 101 copies/μl for HPV16 and 18 respectively, which were comparable to those of the real-time PCR assay. Assessment of the clinical performance of the ERA assays using 114 cervical tissue samples demonstrated that they are highly consistent with real-time PCR, the gold standard for HPV detection. This study demonstrated that ERA-based assays possess excellent sensitivity, specificity, and repeatability for HPV16 and HPV18 detection with great potential to become robust diagnostic tools in local hospitals and field studies.

Immunochromatographic Strip Assay for Detection of Cronobacter sakazakii in Pure Culture

( Xinjie Song ),( Shruti Shukla ),( Gibaek Lee ),( Myunghee Kim ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11

Cronobacter sakazakii (C. sakazakii) is a foodborne pathogen, posing a high risk of disease to infants and immunocompromised individuals. In order to develop a quick, easy, and sensitive assay for detecting C. sakazakii, a rabbit anti-C. sakazakii immunoglobulin G (IgG) was developed using sonicated cell protein from C. sakazakii. The developed anti-C. sakazakii (IgG) was of good quality and purity, as well as species-specific. The developed rabbit anti-C. sakazakii IgG was attached to the surface of a sulforhodamine B-encapsulated liposome to form an immunoliposome. A test strip was then prepared by coating goat anti-rabbit IgG onto the control line and rabbit anti-C. sakazakii IgG onto the test line, respectively, of a plastic-backed nitrocellulose membrane. A purple color signal both on the test line and the control line indicated the presence of C. sakazakii in the sample, whereas purple color only on the control line indicated the absence of C. sakazakii in the sample. This immunochromatographic strip assay could produce results in 15 min with a limit of detection of 107 CFU/ml in C. sakazakii culture. The immunochromatographic strip assay also showed very good specificity without cross-reactivity with other tested Cronobacter species. Based on these results, the developed immunochromatographic strip assay is efficient for the detection of C. sakazakii and has high potential for on-site detection.