Comparison of an Immunochromatographic AssayKit with DAS-ELISA for Large-Scale Diagnosis and Molecular Discrimination of Satsuma Dwarf Virus Collected from Citrus Orchards
Satsuma dwarf virus (SDV) seriously damages citrus production by reducing the quality and yield of fruit. To avoid contamination with SDV, mother trees are checked to be SDV-free in advance of nursery tree distribution. In this study, we compared an immunochromatographic assay (ICA) kit with double-antibody sandwich enzyme-linked immunosorbent assay (DASELISA) for large-scale diagnosis of SDV in orchardgrown trees in Shizuoka Prefecture, Japan. The two methods gave conflicting results for 11 of 1,705 samples, all of which were negative by DAS-ELISA but positive by ICA.
The samples scored as positive by either DASELISA or ICA were analyzed by reverse transcription polymerase chain reaction and all were confirmed to be positive. These results validate the use of ICA as a screening method for large-scale diagnosis. Strain discrimination revealed that 16 of 22 isolates belonged to SDV, while citrus mosaic virus (CiMV) infection only and co-infection (SDV and CiMV) were in a minority.
Description: The Homogeneous Caspase-6 Assay Kit is a complete assay system designed to measure Caspase-6 activity for screening and profiling applications. It comes in a convenient 96-well format, with all the reagents necessary for 100 fluorescent Caspase-6 activity measurements. In addition, the kit includes purified Caspase-6 enzyme and a potent Caspase-6 inhibitor, Ac-IETD-CHO, for use as a positive and negative control. Using this kit, only one simple step on a microtiter plate is needed to analyze the Caspase-6 activity level. The fluorogenic substrate, Ac-VEID-AFC, is incubated with purified Caspase-6 and the enzymatic activity releases AFC fluorophore that can then be measured using a fluorescence reader.
Description: The Homogeneous Caspase-3 Assay Kit is a complete assay system designed to measure Caspase-3 activity for screening and profiling applications. It comes in a convenient 96-well format, with all the reagents necessary for 100 fluorescent Caspase-3 activity measurements. In addition, the kit includes purified Caspase-3 enzyme and a potent Caspase-3 inhibitor, Ac-DNLD-CHO, for use as a positive and negative control. Using this kit, only one simple step on a microtiter plate is needed to analyze the Caspase-3 activity level. The fluorogenic substrate, Ac-DEVD-AFC, is incubated with purified Caspase-3 and the enzymatic activity releases AFC fluorophore that can then be measured using a fluorescence reader.
Description: The Homogeneous Caspase-7 Assay Kit is a complete assay system designed to measure Caspase-7 activity for screening and profiling applications. It comes in a convenient 96-well format, with all the reagents necessary for 100 fluorescent Caspase-7 activity measurements. In addition, the kit includes purified Caspase-7 enzyme and a potent Caspase-3/7 inhibitor, Ac-DNLD-CHO, for use as a positive and negative control. Using this kit, only one simple step on a microtiter plate is needed to analyze the Caspase-7 activity level. The fluorogenic substrate, Ac-DEVD-AFC, is incubated with purified Caspase-7 and the enzymatic activity releases AFC fluorophore that can then be measured using a fluorescence reader.
Description: The Homogeneous Caspase-8 Assay Kit is a complete assay system designed to measure Caspase-8 activity for screening and profiling applications. It comes in a convenient 96-well format, with all the reagents necessary for 100 fluorescent Caspase-8 activity measurements. In addition, the kit includes purified Caspase-8 enzyme and a potent Caspase-8 inhibitor, Ac-IETD-CHO, for use as a positive and negative control. Using this kit, only one simple step on a microtiter plate is needed to analyze the Caspase-8 activity level. The fluorogenic substrate, Ac-IETD-AFC, is incubated with purified Caspase-8 and the enzymatic activity releases AFC fluorophore that can then be measured using a fluorescence reader.
A Preliminary Study on the Ability of the Trypsin-Like Peptidase Activity AssayKit to Detect Periodontitis
This study aimed to explore whether the Trypsin-Like Peptidase Activity Assay Kit (TLP-AA-Kit), which measures the activity of N-benzoyl-dl-arginine peptidase (trypsin-like peptidase), can be used as a reliable tool for periodontitis detection in population-based surveillance. In total, 105 individuals underwent a full-mouth periodontal examination and provided tongue swabs as specimens for further analyses. The results of the TLP-AA-Kit were scored between 1 and 5; higher scores indicated higher trypsin concentrations. Receiver operating characteristic analyses were used to evaluate the predictive validity of the TLP-AA-Kit, where the periodontitis case definition provided by the Centers for Disease Control/American Academy of Periodontology served as the reference.
Severe and moderate periodontitis were identified in 4.8% and 16.2% of the study population, respectively. The TLP-AA-Kit showed high diagnostic accuracy for severe periodontitis, with an area under the curve of 0.93 (95% confidence interval = 0.88-0.99). However, the diagnostic accuracy of the TLP-AA-Kit for moderate/severe periodontitis was not reliable. While further studies are necessary to validate our results, the results provided herein highlight the potential of the TLP-AA-Kit as a useful tool for the detection of periodontitis, particularly in severe cases, for population-based surveillance.
Comparative Performance of SARS-CoV-2 Detection Assays using Seven Different Primer/Probe Sets and One AssayKit
More than 100,000 people worldwide are known to have been infected with SARS-CoV-2 beginning in December 2019. The virus has now spread to over 93 countries including the United States, with the largest cluster of US cases to date in the Seattle metropolitan area in Washington. Given the rapid increase in the number of local cases, the availability of accurate, high-throughput SARS-CoV-2 testing is vital to efforts to manage the current public health crisis. In the course of optimizing SARS-CoV-2 testing performed by the University of Washington Clinical Virology Lab (UW Virology Lab), we tested assays using seven different primer/probe sets and one assay kit.
We found that the most sensitive assays were those the used the E-gene primer/probe set described by Corman et al. (Eurosurveillance 25(3), 2020, https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045) and the N2 set described by the CDC (Division of Viral Diseases, Centers for Disease Control and Prevention, 2020, https://www.cdc.gov/coronavirus/2019-ncov/downloads/rt-pcr-panel-primer-probes.pdf). All assays tested were found to be highly specific for SARS-CoV-2, with no cross-reactivity with other respiratory viruses observed in our analyses regardless of the primer/probe set or kit used. These results will provide invaluable information to other clinical laboratories who are actively developing SARS-CoV-2 testing protocols at a time when increased testing capacity is urgently needed worldwide.
Comparative Performance of SARS-CoV-2 Detection Assays using Seven Different Primer/Probe Sets and One AssayKit.
Nearly 400,000 people worldwide are known to have been infected with SARS-CoV-2 beginning in December 2019. The virus has now spread to over 168 countries including the United States, where the first cluster of cases was observed in the Seattle metropolitan area in Washington. Given the rapid increase in the number of cases in many localities, the availability of accurate, high-throughput SARS-CoV-2 testing is vital to efforts to manage the current public health crisis.
In the course of optimizing SARS-CoV-2 testing performed by the University of Washington Clinical Virology Lab (UW Virology Lab), we evaluated assays using seven different primer/probe sets and one assay kit. We found that the most sensitive assays were those that used the E-gene primer/probe set described by Corman et al. (Eurosurveillance 25 (3), 2020, https://doi.org/10.2807/1560-7917.ES.2020.25.3.2000045) and the N2 set developed by the CDC (Division of Viral Diseases, Centers for Disease Control and Prevention, 2020,
All assays tested were found to be highly specific for SARS-CoV-2, with no cross-reactivity with other respiratory viruses observed in our analyses regardless of the primer/probe set or kit used. These results will provide valuable information to other clinical laboratories who are actively developing SARS-CoV-2 testing protocols at a time when increased testing capacity is urgently needed worldwide.
Development and validation of a rapid kit for authenticity of murine meat in meat products with a species-specific PCR assay.
Adulteration of meat products with murine meat poses a huge threat to consumer health and leads to serious disruption in food markets. Species authentication of murine meat is still technically challenging. We, therefore, developed a species-specific PCR kit consisting of murine meat DNA extraction, PCR reaction and identifying systems. We designed novel universal primers targeting highly conserved region on mitochondrial cytochrome b gene (cyt b) from four murines (lab rats, lab mice, wild rat and wild mice), as well as specific primers for meat from four widely consumed animal species, cattle, sheep, duck and donkey. Simultaneously, pasmid inserted specific cyt b fragment was cloned and used as the internal positve control in the kit. The kit parameters of specificity, sensitivity, stability and validity were determined using mimic counterfeiting meatball.
The specificity of the DNA detection kit was 100% in authentication of the four fraudulent meats of cattle, sheep, duck and donkey mixed murine meat. The minimum detection limit of the sample DNA was 0.1 μg. The kit, which had freeze-thawed up to 20 times and stored for 1 year, also was powerful in detecting an amount of 0.1 mg in artificial counterfeited cattle, sheep, duck and donkey meat products. The murine-species DNA detection kit proposed in this study has proved to be a simple, accurate and effective assay, and can be applied to the identification of murine meat traces in common edible meat, to ensure the realisable implementation of meat product market supervision.
