scholarly journals Association of ‘Candidatus Liberibacter solanacearum’ with a Vegetative Disorder of Celery in Spain and Development of a Real-Time PCR Method for Its Detection

2014 ◽  
Vol 104 (8) ◽  
pp. 804-811 ◽  
Author(s):  
Gabriela R. Teresani ◽  
Edson Bertolini ◽  
Ana Alfaro-Fernández ◽  
Carmen Martínez ◽  
Francisco André Ossamu Tanaka ◽  
...  
Keyword(s):  
Real Time ◽  
Apium Graveolens ◽  
Candidatus Liberibacter Solanacearum ◽  
Test Kit ◽  
Typical Morphology ◽  
Candidatus Liberibacter ◽  
Pcr Method ◽  
Polymerase Chain ◽  
Celery Plant ◽  
Rna Genes

A new symptomatology was observed in celery (Apium graveolens) in Villena, Spain in 2008. Symptomatology included an abnormal amount of shoots per plant and curled stems. These vegetative disorders were associated with ‘Candidatus Liberibacter solanacearum’ and not with phytoplasmas. Samples from plant sap were immobilized on membranes based on the spot procedure and tested using a newly developed real-time polymerase chain reaction assay to detect ‘Ca. L. solanacearum’. Then, a test kit was developed and validated by intralaboratory assays with an accuracy of 100%. Bacterial-like cells with typical morphology of ‘Ca. Liberibacter’ were observed using electron microscopy in celery plant tissues. A fifth haplotype of ‘Ca. L. solanacearum’, named E, was identified in celery and in carrot after analyzing partial sequences of 16S and 50S ribosomal RNA genes. From our results, celery (family Apiaceae) can be listed as a new natural host of this emerging bacterium.

scholarly journals Development of multiplex real-time RT-PCR assay for the detection of SARS-CoV-2

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250942
Author(s):  
Huseyin Tombuloglu ◽  
Hussein Sabit ◽  
Ebtesam Al-Suhaimi ◽  
Reem Al Jindan ◽  
Khaled R. Alkharsah
Keyword(s):  
Real Time ◽  
Single Gene ◽  
False Negative ◽  
Diagnostic System ◽  
Virus Detection ◽  
Current Method ◽  
Pcr Method ◽  
Polymerase Chain ◽  
Positive Results ◽  
Good Agreement

The outbreak of the new human coronavirus SARS-CoV-2 (also known as 2019-nCoV) continues to increase globally. The real-time reverse transcription polymerase chain reaction (rRT-PCR) is the most used technique in virus detection. However, possible false-negative and false-positive results produce misleading consequences, making it necessary to improve existing methods. Here, we developed a multiplex rRT-PCR diagnostic method, which targets two viral genes (RdRP and E) and one human gene (RP) simultaneously. The reaction was tested by using pseudoviral RNA and human target mRNA sequences as a template. Also, the protocol was validated by using 14 clinical SARS-CoV-2 positive samples. The results are in good agreement with the CDC authorized Cepheid`s Xpert® Xpress SARS-CoV-2 diagnostic system (100%). Unlike single gene targeting strategies, the current method provides the amplification of two viral regions in the same PCR reaction. Therefore, an accurate SARS-CoV-2 diagnostic assay was provided, which allows testing of 91 samples in 96-well plates in per run. Thanks to this strategy, fast, reliable, and easy-to-use rRT-PCR method is obtained to diagnose SARS-CoV-2.

Quantitative Real-Time Polymerase Chain Reaction Detection of BK Virus Using Labeled Primers

2010 ◽  
Vol 134 (3) ◽  
pp. 444-448 ◽  
Author(s):  
Zhengming Gu ◽  
Jianmin Pan ◽  
Matthew J. Bankowski ◽  
Randall T. Hayden
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Quantitative Polymerase Chain Reaction ◽  
Bk Virus ◽  
Clinical Samples ◽  
Quantitative Detection ◽  
Chain Reaction ◽  
Pcr Method ◽  
Polymerase Chain

Abstract Context.—BK virus infections among immunocompromised patients are associated with disease of the kidney or urinary bladder. High viral loads, determined by quantitative polymerase chain reaction (PCR), have been correlated with clinical disease. Objective.—To develop and evaluate a novel method for real-time PCR detection and quantification of BK virus using labeled primers. Design.—Patient specimens (n = 54) included 17 plasma, 12 whole blood, and 25 urine samples. DNA was extracted using the MagNA Pure LC Total Nucleic Acid Isolation Kit (Roche Applied Science, Indianapolis, Indiana); sample eluate was PCR-amplified using the labeled primer PCR method. Results were compared with those of a user-developed quantitative real-time PCR method (fluorescence resonance energy transfer probe hybridization). Results.—Labeled primer PCR detected less than 10 copies per reaction and showed quantitative linearity from 101 to 107 copies per reaction. Analytical specificity of labeled primer PCR was 100%. With clinical samples, labeled primer PCR demonstrated a trend toward improved sensitivity compared with the reference method. Quantitative assay comparison showed an R2 value of 0.96 between the 2 assays. Conclusions.—Real-time PCR using labeled primers is highly sensitive and specific for the quantitative detection of BK virus from a variety of clinical specimens. These data demonstrate the applicability of labeled primer PCR for quantitative viral detection and offer a simplified method that removes the need for separate oligonucleotide probes.

scholarly journals In Planta Distribution of ‘Candidatus Liberibacter asiaticus’ as Revealed by Polymerase Chain Reaction (PCR) and Real-Time PCR

2008 ◽  
Vol 98 (5) ◽  
pp. 592-599 ◽  
Author(s):  
Satyanarayana Tatineni ◽  
Uma Shankar Sagaram ◽  
Siddarame Gowda ◽  
Cecile J. Robertson ◽  
William O. Dawson ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Real Time Pcr ◽  
Citrus Tree ◽  
Candidatus Liberibacter Asiaticus ◽  
In Planta ◽  
Chain Reaction ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Polymerase Chain

Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide, and is caused by a phloem-limited fastidious prokaryotic α-proteobacterium that is yet to be cultured. In this study, a combination of traditional polymerase chain reaction (PCR) and real-time PCR targeting the putative DNA polymerase and 16S rDNA sequence of ‘Candidatus Liberibacter asiaticus,’ respectively, were used to examine the distribution and movement of the HLB pathogen in the infected citrus tree. We found that ‘Ca. Liberibacter asiaticus’ was distributed in bark tissue, leaf midrib, roots, and different floral and fruit parts, but not in endosperm and embryo, of infected citrus trees. Quantification analysis of the HLB bacterium indicated that it was distributed unevenly in planta and ranged from 14 to 137,031 cells/μg of total DNA in different tissues. A relatively high concentration of ‘Ca. Liberibacter asiaticus’ was observed in fruit peduncles. Our data from greenhouse-infected plants also indicated that ‘Ca. Liberibacter asiaticus’ was transmitted systemically from infection site to different parts of the plant. Understanding the distribution and movement of the HLB bacterium inside an individual citrus tree is critical for discerning its virulence mechanism and to develop management strategies for HLB.

scholarly journals Translocation of ‘Candidatus Liberibacter solanacearum’, the Zebra Chip Pathogen, in Potato and Tomato

2011 ◽  
Vol 101 (11) ◽  
pp. 1285-1291 ◽  
Author(s):  
Julien Levy ◽  
Aravind Ravindran ◽  
Dennis Gross ◽  
Cecilia Tamborindeguy ◽  
Elizabeth Pierson
Keyword(s):  
Potato Production ◽  
Potato Cultivars ◽  
Zebra Chip ◽  
Tomato Plants ◽  
Candidatus Liberibacter Solanacearum ◽  
Single Leaf ◽  
Zebra Chip Disease ◽  
Candidatus Liberibacter ◽  
Inoculation Access Period ◽  
Polymerase Chain

Zebra Chip disease is a serious threat to potato production. The pathogen, the phloem-limited bacterium ‘Candidatus Liberibacter solanacearum,’ is vectored by the potato and tomato psyllid Bactericerca cockerelli to potato and tomato. Patterns of pathogen translocation through phloem in potato and tomato plants were examined to determine whether rate or direction of translocation vary by host species or potato cultivars. Two insects were given a 7-day inoculation access period on a single leaf. Weekly, leaves from upper-, middle-, and lower-tier branches were tested for the presence of ‘Ca. L. solanacearum’ by polymerase chain reaction (PCR). In tomato and potato, ‘Ca. L. solanacearum’ was detected 2 to 3 weeks after infestation, most frequently in upper- and middle-tier leaves. In potato, the pathogen was detected in leaves on a second, noninfested stem when the stems remained joined via the tuber. Although rates of pathogen movement were similar among potato cultivars, symptoms developed earlier in more susceptible cultivars. Quantitative PCR indicated that bacterial titers were frequently low in tomato and potato samples (<20 genome units per nanogram of DNA). Results establish that, for improved detection, samples should include newly developing leaves and consider that, under low insect pressure, the pathogen may be undetectable by PCR until 3 weeks after infestation.

Quantitative assessment of hematopoietic chimerism after bone marrow transplantation by real-time quantitative polymerase chain reaction

Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4618-4625 ◽  
Author(s):  
Mehdi Alizadeh ◽  
Marc Bernard ◽  
Bruno Danic ◽  
Charly Dauriac ◽  
Brigitte Birebent ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Stem Cell ◽  
Real Time ◽  
Real Time Pcr ◽  
Quantitative Assessment ◽  
Quantitative Polymerase Chain Reaction ◽  
Chain Reaction ◽  
Hematopoietic Stem ◽  
Pcr Method ◽  
Polymerase Chain

We have developed a real-time quantitative polymerase chain reaction (PCR) assay using TaqMan technology (Applied Biosystems, Foster City, CA) for monitoring donor cell engraftment in allogenic hematopoietic stem cell transplant recipients. For this purpose, we selected 19 specific sequence polymorphisms belonging to 11 human biallelic loci located on 9 different chromosomes. Using a set of specially designed primers and fluorogenic probes, we evaluated the 19 markers' informativity on a panel of 126 DNA samples from 63 recipient/donor pairs. In more than 90% of these pairs, discrimination between recipient and donor genetic profile was possible. By using serial dilutions of mixed DNAs, we evaluated the linearity and sensitivity of the method. A linear correlation with rhigher than 0.98 and a sensitivity of 0.1% proved reproducible. Fluorescent-based PCR of short tandem repeats (STR-PCR) and real-time PCR chimerism assay were compared with a panel of artificial cell mixtures. The main advantage of the real-time PCR method over STR-PCR chimerism assays is the absence of PCR competition and plateau biases, and results evidenced greater sensitivity and linearity with the real-time PCR method. Furthermore, different samples can be tested in the same PCR run with a final result in fewer than 48 hours. Finally, we prospectively analyzed patients who received allografts and present 4 different clinical situations that illustrate the informativity level of our method. In conclusion, this new assay provides an accurate quantitative assessment of mixed chimerism that can be useful in guiding early implementation of additional treatments in hematopoietic stem cell transplantation.

scholarly journals Deteksi Plasmodium falciparum dengan menggunakan metode real-time polymerase chain reaction di daerah Likupang dan Bitung

2016 ◽  
Vol 4 (1) ◽  
Author(s):  
David C. Tooy ◽  
Janno B. Bernadus ◽  
Angle Sorisi
Keyword(s):  
Polymerase Chain Reaction ◽  
Plasmodium Falciparum ◽  
Real Time ◽  
Real Time Pcr ◽  
18S Rrna ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Negative Results ◽  
Pcr Method ◽  
Polymerase Chain

Abstract: Malaria is one of the most important parasitic disease which is caused by Plasmodium spp. There are approximately 1,2 billion people in the world with high risk of getting malaria. Plasmodium falciparum (P. falciparum) is the cause of tropical malaria or falciparum malaria, and is responsible for most of the mortality rate. Currently, real-time polymerase chain reaction (RT-PCR) is being studied as an alterative of conventional malarian examination. Mangold et al reported that RT-PCR have 94.1% sensitivity and 100% specificity compared to microscopic examination in detecting P. falciparum. The aim of this research is to detect the presence of P. falciparum using RT-PCR in Likupang and Bitung region. This research were using descriptive design to find out the capability of real-time PCR method to detect P. falciparum in Likupang dan Bitung region. The researcher have examined 71 samples which are fulfill the research sample’s criteria. Postive results of P. falciparum found in 18 samples (25,3%) and negative results in 53 samples (74,6%) of total 71 samples with using RT-PCR. No positive results were found in samples from Likupang. There are positive result of P. falciparum in samples from Bitung. It is concluded that RT-PCR method can detect the presence of P. falciparum from the samples obtained from Likupang and Bitung based on the presence of its DNA. This detection efford is done by using 18S rRNA as target gene and ajust specific temperature on the RT-PCR instrument.Keywords: Plasmodium falciparum, Real-time Polymerase Chain Reaction (PCR), DetectionAbstrak: Malaria merupakan salah satu penyakit penting yang disebabkan oleh parasit Plasmodium spp. Kira-kira 1,2 miliar penduduk dunia memiliki risiko tinggi untuk mendapat malaria. Di Indonesia sendiri, terdapat 343.527 kasus terkonfirmasi dan 45 kematian karena malaria. Plasmodium falciparum (P. Falciparum) merupakan penyebab dari malaria tropika atau malaria falsiparum, dan bertanggung jawab atas sebagian besar angka mortalitas. Saat ini Real-Time Polymerase Chain Reaction (RT-PCR) telah banyak diteliti sebagai alternatif dari pemeriksaan malaria. Mangold dkk melaporkan bahwa real-time PCR memiliki nilai sensitivitas 94,1% dan nilai spesifisitas 100% terhadap pemeriksaan mikroskopis dalam mendeteksi P. falciparum. Penelitian bertujuan untuk mendeteksi P. falciparum dengan menggunakan RT-PCR di daerah Likupang dan Bitung. Penelitian ini menggunakan rancangan penelitian deskriptif untuk mengetahui kemampuan metode real-time PCR dalam mendeteksi P. falciparum di daerah Likupang dan Bitung. Tujuan penelitian ini ialah untuk mendeteksi keberadaan P. falciparum dengan menggunakan metode real-time PCR di daerah Likupang dan Bitung. Peneliti memeriksa 71 sampel darah yang memenuhi kriteria sampel penelitian. Hasil positif P. falciparum ditemukan pada 18 sampel (25,3 %) dan hasil negatif pada 53 sampel (74,6 %) dari total 71 sampel dengan menggunakan RT-PCR. Tidak ditemukannya hasil positif P. falciparum pada sampel dari Likupang. Ditemukan hasil positif P. falciparum pada sampel dari Bitung. Simpulan: Metode RT-PCR dapat mendeteksi P. falciparum berdasarkan keberadaan DNA-nya pada sampel yang diperoleh dari daerah Likupang dan Bitung. Deteksi ini berhasil dilakukan dengan menggunakan 18S rRNA sebagai gen target dan pengaturan suhu tertentu pada instrument RT-PCR.Kata kunci: P. falciparum, Real-time Polymerase Chain Reaction (PCR), Detection

scholarly journals First Report of ‘Candidatus Liberibacter solanacearum’ in Carrot in France

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 839-839 ◽  
Author(s):  
M. Loiseau ◽  
S. Garnier ◽  
V. Boirin ◽  
M. Merieau ◽  
A. Leguay ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Real Time ◽  
16S Rdna ◽  
Real Time Pcr ◽  
Germination Rate ◽  
Ammonium Bromide ◽  
Ribosomal Protein Genes ◽  
Candidatus Liberibacter Solanacearum ◽  
First Report ◽  
Candidatus Liberibacter

In summer 2012, carrot (Daucus carota L.) plants displaying symptoms of leaf yellowing, stunting and proliferation of dwarfed shoots with bushy tops, and a dense hairy growth of secondary roots were observed. Symptomatic carrots were collected from three fields used for seed production and located in Region Centre of France near Orléans. The presence of psyllids (Psyllidae) in one of the fields was reported but they were not clearly identified. Fifty percent of the field was infected. Due to a large amount of plant debris, the harvested seeds were difficult to separate and the germination rate was low (from 10 to 77%), rendering them unmarketable. The symptoms observed were similar to those described for carrots infected by Aster yellows phytoplasma and ‘Candidatus Liberibacter solanacearum’ in Europe (3). Total DNA was extracted from petiole and root tissue of 16 symptomatic and 6 asymptomatic carrots (cv. Amsterdam, CAC3075), 2 samples of black nightshade leaves (Solanum nigrum) collected from the same fields, and 2 samples of carrot plants (cv Berlicum) grown in a high containment greenhouse, using a cetyl trimethyl ammonium bromide (CTAB) buffer extraction method. All DNA extracts were tested for phytoplasmas (1) and for ‘Ca. L. solanacearum’ by real-time PCR (2). DNA extracts were also tested for ‘Ca. L. solanacearum’ by PCR using primer pairs OA2/OI2c and CL514F/R to amplify a portion of 16S rDNA and rpIJ/rpIL ribosomal protein genes, respectively (4). DNA from greenhouse carrot plants yielded no amplicon with all PCR. Phytoplasma was not detected in any of the tested samples. However, amplification was observed with the real-time PCR assay for ‘Ca. L. solanacearum’ (2) for all DNA samples extracted from symptomatic and asymptomatic field carrots (cycle threshold [ct] values between 16.75 and 30.59), and from S. nigrum (ct between 31.62 and 33.25). For field carrot DNA, a 1,168-bp 16S rDNA fragment and a 669-bp rpIJ/rpIL fragment were amplified whereas DNA from S. nigrum yielded no amplicon. Four amplicons obtained from these PCR assays with both primer pairs from symptomatic carrot samples were sequenced directly (Beckmann Coulter Genomics, Grenoble, France). BLAST analysis of the 16S rDNA sequences (KF357911) showed 99% nucleotide identity to those of ‘Ca. L. solanacearum’ amplified from carrot in Finland (GU373049). The rpIJ/rpIL nucleotide sequences (KF357912) were 99% identical to sequences of the analogous rpIJ/rpIL ‘Ca. L. solanacearum’ ribosomal protein gene from carrot in Spain (JX308305). These results confirmed the presence of ‘Ca. L. solanacearum’ in all symptomatic and asymptomatic carrot sampled in Region Centre, France. To our knowledge, this is the first report of this pathogen in carrot in France. These results, in addition to those previously obtained (4), suggest a wider distribution of ‘Ca. L. solanacearum’ than previously reported in Europe and should lead plant health managers to consider this pathogen as an emerging threat. References: (1) N. M. Christensen et al. Mol. Plant Microbe Interact. 17:1175, 2004. (2) W. Li et al. J. Microbiol. Methods 78:59, 2009. (3) J. E. Munyaneza et al. Plant Dis. 94:639, 2010. (4) J. E. Munyaneza et al. Plant Dis. 96:453, 2012.

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