scholarly journals Flinders technology associates (FTA) filter paper–based DNA extraction with polymerase chain reaction (PCR) for detection ofPneumocystis jirovecii from respiratory specimens of immunocompromised patients

2007 ◽  
Vol 21 (6) ◽  
pp. 382-386 ◽  
Author(s):  
Surang Nuchprayoon ◽  
Wilai Saksirisampant ◽  
Siraya Jaijakul ◽  
Issarang Nuchprayoon
2013 ◽  
Vol 55 (3) ◽  
pp. 205-208 ◽  
Author(s):  
Renata Bortolasse Miguel ◽  
José Rodrigues Coura ◽  
Franklyn Samudio ◽  
Martha Cecília Suárez-Mutis

Asymptomatic Plasmodium infection is a new challenge for public health in the American region. The polymerase chain reaction (PCR) is the best method for diagnosing subpatent parasitemias. In endemic areas, blood collection is hampered by geographical distances and deficient transport and storage conditions of the samples. Because DNA extraction from blood collected on filter paper is an efficient method for molecular studies in high parasitemic individuals, we investigated whether the technique could be an alternative for Plasmodium diagnosis among asymptomatic and pauciparasitemic subjects. In this report we compared three different methods (Chelex®-saponin, methanol and TRIS-EDTA) of DNA extraction from blood collected on filter paper from asymptomatic Plasmodium-infected individuals. Polymerase chain reaction assays for detection of Plasmodium species showed the best results when the Chelex®-saponin method was used. Even though the sensitivity of detection was approximately 66% and 31% for P. falciparum and P. vivax, respectively, this method did not show the effectiveness in DNA extraction required for molecular diagnosis of Plasmodium. The development of better methods for extracting DNA from blood collected on filter paper is important for the diagnosis of subpatent malarial infections in remote areas and would contribute to establishing the epidemiology of this form of infection.


Author(s):  
Dwiyitno Dwiyitno ◽  
Stefan Hoffman ◽  
Koen Parmentier ◽  
Chris Van Keer

Fish and seafood products has been commonly targeted for fraudulent activities. For that reason, authentication of fish and seafood products is important to protect consumers from fraudulent and adulteration practices, as well as to implement traceability regulation. From the viewpoint of food safety, authenticity is beneficial to protect public from serious food poisoning incidents, such as due to ingestion of toxic species. Since DNA based identification depends on the nucleic acid polymerase chain reaction (PCR), the quantity and quality/purity of DNA will contribute significantly to the species authentication. In the present study, different DNA extraction and purification methods (3 classical methods and one commercial kit) were compared to produce the better isolated DNA for PCR amplification. Additionally, different methods for the estimation of DNA concentration and purity which is essential for PCR amplification efficiency were also evaluated. The result showed that classical DNA extraction methods (based on TNES-Urea) yielded a higher amount of DNA (11.30-323.60 ng/g tissue) in comparison to commercial kit/Wizard Promega (5.70-83.45 ng/g tissue). Based on the purity of DNA extract (A260/280), classical DNA extraction method produced relatively similar on DNA quality to the commercial kit (1.79-2.12). Interestingly, all classical methods produced DNA with A260/280 ratio of more than 2.00 on the blue mussel, in contrast with commercial kit. The commercial kit also produced better quality of DNA compared to the classical methods, showing the higher efficiency in PCR amplification. NanoDrop is promising as cheap, robust and safe UV-spectrophotometer method for DNA quantification, as well as the purity evaluation.Keywords: seafood authenticity, DNA isolation, polymerase chain reaction, NanoDrop, Picogreen


2021 ◽  
Vol 9 ◽  
pp. 2050313X2110400
Author(s):  
Bilal Chaudhry ◽  
Lidiya Didenko ◽  
Maaria Chaudhry ◽  
Andrew Malek ◽  
Kirill Alekseyev

Coronavirus 2019 (COVID-19) pneumonia was first noted in Wuhan, China. Since the start of the pandemic, there have been millions of cases diagnosed. The average time from onset of symptoms to testing negative SARS-CoV-2 via reverse transcription polymerase chain reaction is roughly 25 days. In patients who continually test positive for COVID-19, it is essential to determine precisely which risk factors contribute to the increase in viral shedding duration. We present a case about a 62-year-old man who has persistently tested positive for COVID-19 for more than 230 days. We followed his treatment course, in which he had been hospitalized multiple times since the onset of symptoms back in April 2020. We have determined that patients with immunosuppression, especially those taking corticosteroids, are at increased risk of prolonged viral shedding. It is essential to continually monitor these immunocompromised patients as they required a greater time period in order to have an appropriate immune response in which antibodies are created.


Author(s):  
Fernanda Pinto-Ferreira ◽  
Jonatan Batista Reis ◽  
Aline Ticiani Pereira Paschoal ◽  
Letícia Santos Balbino ◽  
Amanda Bertão-Santos ◽  
...  

Abstract The consumption of vegetables has increased in recent years due to the search for a healthier diet that is rich in fiber and has fewer calories. To assess the parasitic contamination of lettuce sold in markets, a survey of parasites was carried out from a supermarket chain in the city of Londrina, Paraná. A total of thirty samples of lettuce were purchased in the ten markets visited, three in each, of which ten were conventionally cultivated, ten were hydroponically cultivated, and ten were organically cultivated. All samples were analyzed using the sedimentation methods of Hoffman, Pons and Janer and the fluctuation method of Faust and colleagues and Willis with adaptations. In addition, the samples were subjected to DNA extraction by a commercial kit and polymerase chain reaction to detect Toxoplasma gondii, Cryptosporidium spp. and Giardia spp., which are protozoa that cause food and waterborne parasitic outbreaks. All samples were negative for sedimentation and flotation techniques. One of the hydroponically cultivated samples was positive for T. gondii. The results demonstrate the risk of curly lettuce contamination from hydroponic cultivation and the need for proper cleaning of these foods before consumption.


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