scholarly journals Using the TxtAB Operon to Quantify Pathogenic Streptomyces in Potato Tubers and Soil

2008 ◽  
Vol 98 (4) ◽  
pp. 405-412 ◽  
Author(s):  
Xinshun Qu ◽  
Leslie A. Wanner ◽  
Barbara J. Christ

The phytotoxin thaxtomin, produced by plant pathogenic Streptomyces species, is the only known pathogenicity determinant for common scab diseases of potato and other root and tuber crops. Genes encoding thaxtomin synthetase (txtAB) are found on a pathogenicity island characteristic of genetically diverse plant pathogenic Streptomyces species. In this study, an SYBR Green quantitative real-time polymerase chain reaction (PCR) assay using primers designed to anneal to the txtAB operon of Streptomyces was developed to quantify pathogenic bacterial populations in potatoes and soil. The real-time PCR assay was specific for pathogenic Streptomyces strains. The detection limit of the assay was 10 fg of the target DNA, or one genome equivalent. Cycle threshold (Ct) values were linearly correlated with the concentration of the target DNA (correlation coefficient R2 = 0.99) and were not affected by the presence of plant DNA extracts, indicating the usefulness of the assay for quantitative analyses of the pathogenic bacteria in plant tissues. The amount of pathogenic Streptomyces DNA in total DNA extracts from 1 g asymptomatic and symptomatic tubers was quantified using the assay and ranged from 101 to 106 pg. A standard curve was established to quantify pathogenic Streptomyces in soil. Using the standard curve, numbers of pathogenic Streptomyces colony forming units were extrapolated to range from 103 to 106 per gram of soil from potato fields where common scab was found. This real-time PCR assay using primers designed from the txtAB operon allows rapid, accurate, and cost effective quantification of pathogenic Streptomyces strains in potato tubers and in soil.

2020 ◽  
Vol 119 (11) ◽  
pp. 3909-3913
Author(s):  
Zaida Rentería-Solís ◽  
Tran Nguyen-Ho-Bao ◽  
Shahinaz Taha ◽  
Arwid Daugschies

Abstract Trichomonas gallinae are parasitic flagellates of importance in wild and domestic birds. The parasite is worldwide distributed, and Columbine birds are its main host. Current research focuses mostly on epidemiological and phylogenetic studies. However, there is still a lack of knowledge regarding parasite-host interaction or therapy development. Real-time PCR is a useful tool for diagnostic and quantification of gene copies in a determined sample. By amplification of a 113-bp region of the 18S small subunit ribosomal RNA gene, a SYBR green-based real-time PCR assay was developed. A standard curve was prepared for quantification analysis. Assay efficiency, linearity, and dissociation analysis were successfully performed. Specificity, sensibility, and reproducibility analysis were tested. This assay could be a useful tool not only for diagnostic purposes but also for future in vivo and in vitro T. gallinae studies.


2010 ◽  
Vol 48 (3) ◽  
pp. 466-469 ◽  
Author(s):  
Kelly W. Sheff ◽  
Emily R. York ◽  
Elizabeth M. Driebe ◽  
Bridget M. Barker ◽  
Steven D. Rounsley ◽  
...  

2021 ◽  
Author(s):  
Haibin Ma ◽  
Yahui Li ◽  
Junzheng Yang

Objectives: To develop a sensitive, highly specific fluorescent quantitative real-time PCR assay for accurate detection and quantification of novel-goose parvovirus (N-GPV) in vitro and in vivo. Methods: Specific primers was designed based on N-GPV inverted terminal repeats region; virus RNA (DFV, NDV, AIV, DHV-1, DHV-3) and virus DNA (MDPV, GPV, N-GPV) were extracted, cDNA (DFV, NDV, AIV, DHV-1, DHV-3) were prepared from viral RNAs using M-MLV Reverse Transcriptase, and prepared cDNA (DFV, NDV, AIV, DHV-1, DHV-3) and DNA (MDPV, GPV, N-GPV) amplified by real-time PCR; the sensitivity, specificity and reproducibility of established real-time PCR methods were evaluated, and finally we validated the reliability of real-time PCR methods in ducklings models in vivo. Results: The standard curve of established real-time PCR had a good linearity (slope was -0.3098, Y-intercept was 37.865, efficiency of standard curve was 0.995); the detection limit of established real-time PCR for N-GPV was 10 copies/reaction. The sensitivity of real-time PCR was 10 copies/uL, which was 1000 times higher than conventional gel-based PCR assay. The results of intra-assay CVs (0.04-0.74%) and inter-assay CVs (0.16-0.53%) showed that the real-time PCR assay had an excellent repeatability. This method also could efficiently detect viral load in heart, liver, spleen, lung, kidney, pancreas, bursa of Fabricius, brain, blood and excrement from ducklings models after N-GPV infection from 6h to 28 days, which could provided us a dynamic distribution observation of N-GPV viral load using this real-time PCR assay in vivo. Conclusion: In the study, we developed a high sensitive, specific and reproducible real-time PCR assay for N-GPV detection. The established real-time PCR assay was suitable for parvovirus detection and quantification simultaneously, no matter sample obtained from blood, internal organs or ileac contents; the present work may provide insight into the pathogenesis of N-GPV and will contributes to better understanding of this newly emerged novel GPV related virus in cherry valley ducks.


2016 ◽  
Vol 1 (1) ◽  
pp. 18
Author(s):  
Sonia Arora ◽  
Duraipandian Thavaselvam ◽  
Archna Prakash ◽  
Ashu Kumar ◽  
Anita Barua ◽  
...  

Burkholderia pseudomallei the gram negative, soil saprophyte is the causative agent of melioidosis in human and animals. Development of rapid, sensitive, species specific and cost effective molecular assays are needed for detection of B. pseudomallei from clinical and environmental samples and to differentiate it from other closely related bacterial species. In this study, insilico approach was used to identify new species specific gene targets for molecular diagnosis of B. pseudomallei. The identified targets were then analyzed by SYBR Green real time PCR assay for their specificity, sensitivity and presence across different Indian clinical and soil isolates of B. pseudomallei. Out of the three targets studied SYBR Green real time PCR assay targeting bpss0091 gene of B. pseudomallei was found 100% specific, having detection limit of 12.3fg/µl DNA. The bpss0091 gene target was present in all clinical and soil isolates of B. pseudomallei tested thus suggesting bpss0091 gene based SYBR Green real time PCR assay will be useful for detection of B. pseudomallei in different geographical regions.


2011 ◽  
Vol 29 (7_suppl) ◽  
pp. 271-271
Author(s):  
J. Millholland ◽  
S. G. Patel ◽  
C. A. Fernandez ◽  
A. P. Shuber

271 Background: We have recently reported the development of a Multi-Analyte Diagnostic Readout (MADR) non-invasive assay using urinary matrix metalloproteinases (MMPs) and FGFR3 as triage monitors in high-risk bladder cancer populations. This concept combines the marker performance characteristics of protein and DNA biomarkers into one assay for optimal performance. Eight common FGFR3 mutations in 3 exons have been associated with bladder cancer. Analysis of mutational status for each single mutation required 8 amplification steps, which were costly and time consuming. We have now developed a real-time multiplexed FGFR3 assay, generating a cost-effective, clinically applicable assay for the detection of FGFR3 mutations in urine. Methods: Our approach involves a two-step PCR amplification process. The initial round generates exon specific PCR products, which are then used as template for real-time PCR mutation detection utilizing locked nucleic acid (LNA) oligonucleotides. The LNA suppress wild-type DNA amplification. To convert our existing FGFR3 assay to a multiplex format, primary amplifications of exons 7, 10, and 15 were combined into a single real-time PCR assay for exon specific amplification and DNA quantitation. The LNA-mediated mutation detection was then converted from 4 reactions to 2 duplex amplifications. All multiplex assays were carried out on the Roche LC 480 real-time PCR platform. Results: To validate the new multiplex format, FGFR3 multiplex analysis was performed on DNA isolated from 50 Ta stage bladder tumors. FGFR3 mutations were detected in 90% (48/50) of the tumors. To directly compare performance with single mutation analysis, 40 urine samples previously analyzed using the singleplex format were again tested using the multiplex FGFR3 assay. 100% concordance was seen between the two assay formats. Conclusions: By multiplexing the FGFR3 mutation analysis we reduced the number of amplification steps, improving assay turnaround time and throughput, without compromising assay performance. The FGFR3 multiplex analysis provides a robust, cost-effective DNA assay that in combination with MMP protein analysis delivers a clinically applicable assay with optimal performance. [Table: see text]


2021 ◽  
Author(s):  
Göksel Özer ◽  
Gülsüm Palacıoğlu ◽  
Abdulkadir Aydoğan ◽  
Harun Bayraktar

Abstract Ascochyta blight, caused by Ascochyta rabiei is a devastating disease of chickpea worldwide. Breeding for host resistance is an efficient means to reduce the damage by this pathogen. This study evaluated the utility of Real-time polymerase chain reaction (PCR) assay for screening chickpea genotypes for resistant to blight disease. Eight days after inoculation, the resistance level of 84 chickpea genotypes was quantified by Real-time PCR technique using a standard curve constructed by amplifying different known amounts of target DNA and compared with disease scores based on visual assessment. A significant variation was statistically found among chickpea genotypes with respect to disease reactions. The quantity of target DNA in infected samples varied from 0.004–83.37 ng. The results demonstrated a strong relationship between visual scoring of disease severity and quantification of the target DNA in chickpea genotypes. Tüb-35, Tüb-47, Tüb-26, Tüb-82, Tüb-65 and Tüb-69 genotypes were found highly resistant to Ascochyta blight based on the results of both assays utilized for screening chickpea genotypes for resistance. The real-time PCR assay could be used for quantifying disease progression in plant tissues and screening chickpea genotypes as a potential alternative to visual scoring in plant resistance breeding programs.


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