Development of a Detection Method against 11 Major Pathogens of Honey Bee using Amplification of Multiplex PCR and Specific DNA-chip

Rapidly quantitative detection of Nosema ceranae in honeybees using ultra-rapid real-time quantitative PCR

BACKGROUND

The microsporidian parasite Nosema ceranae is a global problem in honeybee populations and is known to cause winter mortality. A sensitive and rapid tool for stable quantitative detection is necessary to establish further research related to the diagnosis, prevention, and treatment of this pathogen.

OBJECTIVES

The present study aimed to develop a quantitative method that incorporates ultra-rapid real-time quantitative polymerase chain reaction (UR-qPCR) for the rapid enumeration of N. ceranae in infected bees.

METHODS

A procedure for UR-qPCR detection of N. ceranae was developed, and the advantages of molecular detection were evaluated in comparison with microscopic enumeration.

RESULTS

UR-qPCR was more sensitive than microscopic enumeration for detecting two copies of N. ceranae DNA and 24 spores per bee. Meanwhile, the limit of detection by microscopy was 2.40 × 10⁴ spores/bee, and the stable detection level was ≥ 2.40 × 10⁵ spores/bee. The results of N. ceranae calculations from the infected honeybees and purified spores by UR-qPCR showed that the DNA copy number was approximately 8-fold higher than the spore count. Additionally, honeybees infected with N. ceranae with 2.74 × 10⁴ copies of N. ceranae DNA were incapable of detection by microscopy. The results of quantitative analysis using UR-qPCR were accomplished within 20 min.

CONCLUSIONS

UR-qPCR is expected to be the most rapid molecular method for Nosema detection and has been developed for diagnosing nosemosis at low levels of infection.

Rapid detection of deformed wing virus in honeybee using ultra-rapid qPCR and a DNA-chip

Fast and accurate detection of viral RNA pathogens is important in apiculture. A polymerase chain reaction (PCR)-based detection method has been developed, which is simple, specific, and sensitive. In this study, we rapidly (in 1 min) synthesized cDNA from the RNA of deformed wing virus (DWV)-infected bees (Apis mellifera), and then, within 10 min, amplified the target cDNA by ultra-rapid qPCR. The PCR products were hybridized to a DNA-chip for confirmation of target gene specificity. The results of this study suggest that our method might be a useful tool for detecting DWV, as well as for the diagnosis of RNA virus-mediated diseases on-site.

Application of ultra-rapid qPCR and DNA chips for viral RNA detection and confirmation

The rapid and accurate detection of the presence of microorganisms, such as viruses, has been an important issue in the fields of public health, as well as agriculture. A PCR-based detection method has been developed and applied in these fields to determine the presence of specific pathogens. Although the major advantage of real-time PCR is the monitoring of amplification and ability to quantify the template genes, the method described here should solve the problem of nonspecific product synthesis. We obtained viral RNA from infected samples by freezing and thawing; we rapidly synthesized cDNA from RNA, and then amplified the cDNA by rapid PCR in 10 Min. Finally, the PCR products were hybridized and quickly confirmed to be the target analyte on a DNA chip. Our newly proposed methods overcome the drawbacks of PCR-based detection and provide three additional advantages, namely, rapidly obtaining large amounts of RNA from samples, quickly detecting infective or pathogenic genes, and speedily confirming the detected exogenous genes. This application might be useful for detecting viral RNA and for the diagnosis of RNA virus-mediated diseases.