Quantitative detection method of Enterocytozoon hepatopenaei using TaqMan probe real-time PCR

The protozoan Toxoplasma gondii is one of the most common infectious pathogenic parasites and can cause severe medical complications in infants and immunocompromised individuals. We report here the development of a real-time PCR-based assay for the detection of T. gondii. Oligonucleotide primers and a fluorescence-labeled TaqMan probe were designed to amplify the T. gondii B1 gene. After 40 PCR cycles, the cycle threshold values (CT) indicative of the quantity of the target gene were determined. Typically, a CT of 25.09 was obtained with DNA from 500 tachyzoites of the T. gondii RH strain. The intra-assay coefficients of variation (CV) were 0.4, 0.16, 0.24, and 0.79% for the four sets of quadruplicate assays, with a mean interassay CV of 0.4%. These values indicate the reproducibility of this assay. Upon optimization of assay conditions, we were able to obtain a standard curve with a linear range (correlation coefficient = 0.9988) across at least 6 logs of DNA concentration. Hence, we were able to quantitatively detect as little as 0.05 T. gondii tachyzoite in an assay. When tested with 30 paraffin-embedded fetal tissue sections, 10 sections (33%) showed a CT of <40 and were scored as positive for this test. These results were consistent with those obtained through our nested-PCR control experiments. We have developed a rapid, sensitive, and quantitative real-time PCR for detection of T. gondii. The advantages of this technique for the diagnosis of toxoplasmosis in a clinical laboratory are discussed.

Download Full-text

A TaqMan Real-Time PCR Assay for Detection and Quantification ofSporisorium scitamineumin Sugarcane

The Scientific World JOURNAL ◽

10.1155/2013/942682 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Yachun Su ◽

Shanshan Wang ◽

Jinlong Guo ◽

Bantong Xue ◽

Liping Xu ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Management Practice ◽

Taqman Probe ◽

Quantitative Detection ◽

Pcr Assay ◽

Essential Requirement ◽

Sporisorium Scitamineum ◽

Initial Stage ◽

Type Gene

Sporisorium scitamineumis a fungal smut pathogen epidemic in sugarcane producing areas. Early detection and proper identification of the smut are an essential requirement in its management practice. In this study, we developed a TaqMan real-time PCR assay using specific primers (bEQ-F/bEQ-R) and a TaqMan probe (bEQ-P) which were designed based on thebE(b East mating type) gene (Genbank Accession no. U61290.1). This method was more sensitive (a detection limit of 10 ag pbE DNA and 0.8 ng sugarcane genomic DNA) than that of conventional PCR (10 fg and 100 ng, resp.). Reliability was demonstrated through the positive detection of samples collected from artificially inoculated sugarcane plantlets (FN40). This assay was capable of detecting the smut pathogen at the initial stage (12 h) of infection and suitable for inspection of sugarcane pathogen-free seed cane and seedlings. Furthermore, quantification of pathogen was verified in pathogen-challenged buds in different sugarcane genotypes, which suggested its feasibility for evaluation of smut resistance in different sugarcane genotypes. Taken together, this novel assay can be used as a diagnostic tool for sensitive, accurate, fast, and quantitative detection of the smut pathogen especially for asymptomatic seed cane or plants and evaluation of smut resistance of sugarcane genotypes.

Download Full-text

Development of Real-Time Polymerase Chain Reaction Assay with TaqMan Probe for the Quantitative Detection of Infectious Hypodermal and Hematopoietic Necrosis Virus from Shrimp

Journal of AOAC International ◽

10.1093/jaoac/89.1.240 ◽

2006 ◽

Vol 89 (1) ◽

pp. 240-244 ◽

Cited By ~ 5

Author(s):

Zhi-Qin Yue ◽

Hong Liu ◽

Wei-Ji Wang ◽

Zhi-Wen Lei ◽

Cheng-Zhu Liang ◽

...

Keyword(s):

Polymerase Chain Reaction ◽

Real Time ◽

Real Time Pcr ◽

Taqman Probe ◽

Quantitative Detection ◽

Necrosis Virus ◽

Chain Reaction ◽

Pcr Assay ◽

The Real ◽

Polymerase Chain

Abstract An assay was developed for the detection of infectious hypodermal and hematopoietic necrosis virus (IHHNV) based on real-time quantitative polymerase chain reaction (PCR). A pair of primers and a TaqMan probe were designed that are specific for the recognition of a conservative region in the IHHNV genome. The IHHNV real-time PCR assay had a detection limit of 9 DNA copies,with a dynamic range of detection between 9 106 and 9 DNA copies. The primer pairs and probe were specific to IHHNV and did not cross-reactwith shrimp genomic DNAor other shrimp viruses such as White Spot Syndrome Virus (WSSV), Monodon Baculovirus (MBV), and hepatopancreatic parvovirus (HPV). This assay has a broad application for basic and clinical investigations. For clinical samples, the real-time PCR assay detected all the positive samples screened by conventional PCR, which indicated the sensitivity of the real-time assay. The IHHNV real-time PCR assay with high sensitivity, specificity, wide range of detection ability, and simplicity is particularly useful for screening large numbers of specimens and measuring viral loads to monitor the broodstock.

Download Full-text

Quantitative Detection of Clostridium perfringens in the Broiler Fowl Gastrointestinal Tract by Real-Time PCR

Applied and Environmental Microbiology ◽

10.1128/aem.71.7.3911-3916.2005 ◽

2005 ◽

Vol 71 (7) ◽

pp. 3911-3916 ◽

Cited By ~ 71

Author(s):

Mark G. Wise ◽

Gregory R. Siragusa

Keyword(s):

Gastrointestinal Tract ◽

Real Time ◽

Clostridium Perfringens ◽

Real Time Pcr ◽

Limit Of Detection ◽

Quantitative Detection ◽

Necrotic Enteritis ◽

Analytical Sensitivity ◽

Quantitative Real Time Pcr ◽

Pcr Inhibitor

ABSTRACT Strains of Clostridium perfringens are a frequent cause of food-borne disease and gas gangrene and are also associated with necrotic enteritis in chickens. To detect and quantify the levels of C. perfringens in the chicken gastrointestinal tract, a quantitative real-time PCR assay utilizing a fluorogenic, hydrolysis-type probe was developed and utilized to assay material retrieved from the broiler chicken cecum and ileum. Primers and probe were selected following an alignment of 16S rDNA sequences from members of cluster I of the genus Clostridium, and proved to be specific for C. perfringens. The assay could detect approximately 50 fg of C. perfringens genomic DNA and approximately 20 cells in pure culture. Measurements of the analytical sensitivity determined with spiked intestinal contents indicated that the consistent limit of detection with ileal samples was approximately 102 CFU/g of ileal material, but only about 104 CFU/g of cecal samples. The decreased sensitivity with the cecal samples was due to the presence of an unidentified chemical PCR inhibitor(s) in the cecal DNA purifications. The assay was utilized to rapidly detect and quantify C. perfringens levels in the gut tract of broiler chickens reared without supplementary growth-promoting antibiotics that manifested symptoms of necrotic enteritis. The results illustrated that quantitative real-time PCR correlates well with quantification via standard plate counts in samples taken from the ileal region of the gastrointestinal tract.

Download Full-text

Quantitative Detection of Species-Specific DNA in Feedstuffs and Fish Meals

Journal of Food Protection ◽

10.4315/0362-028x-68.6.1217 ◽

2005 ◽

Vol 68 (6) ◽

pp. 1217-1221 ◽

Cited By ~ 27

Author(s):

PAVEL KRCMAR ◽

EVA RENCOVA

Keyword(s):

Mitochondrial Dna ◽

Real Time ◽

Dna Sequences ◽

Real Time Pcr ◽

Single Species ◽

Absolute Quantification ◽

Quantitative Detection ◽

Vertebrate Species ◽

Target Species ◽

Species Specific

A sensitive and rapid method for the quantitative detection of bovine-, ovine-, swine-, and chicken-specific mitochondrial DNA sequences based on real-time PCR has been developed. The specificity of the primers and probes for real-time PCR has been tested using DNA samples of other vertebrate species that may also be present in rendered products. The quantitative detection was performed with dual-labeled probes (TaqMan) using absolute quantification with external standards of single species meat-and-bone meals. This method facilitates the detection of 0.01% of the target species–derived material in concentrate feed mixtures and fish meals.

Download Full-text