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Results for “DNA extraction”

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At least 433 records · Page 24Linked to original sources
PubMed2001

Multicenter comparison trial of DNA extraction methods and PCR assays for detection of Chlamydia pneumoniae in endarterectomy specimens.

The reported rate of detection of Chlamydia pneumoniae DNA within atherosclerotic lesions by PCR varies between 0 and 100%. In this study, identical sets of coded experimental atheroma samples (n = 15) and spiked controls (n = 5) were analyzed by 16 test methods in nine centers by means of PCR. The positive controls were correctly identified to levels of 1, 0.1, and 0.01 inclusion bodies of C. pneumoniae/ml of tissue homogenate by 16 (100%), 11 (69%), and 3 (19%) of the test methods, respectively. Three out of 16 negative controls (19%) were rated positive. Positivity rates for atheroma samples varied between 0 and 60% for the different test methods, with the maximum concordant result for positivity being only 25% for one carotid artery sample. There was no consistent pattern of positive results among the various laboratories, and there was no correlation between the detection rates and the sensitivity of the assay used.

Arteriosclerosis↗
PubMedDate not supplied

Rapid DNA extraction and sensitive alkaline blotting protocol: application for detection of gene rearrangement and amplification for clinical molecular diagnosis.

A simple and sensitive DNA extraction/Southern blotting method is described for the routine detection of gene rearrangement and amplification in DNA samples. Significant features of the procedure are: (1) sequential digestion of RNA and protein in the same DNA buffer; and (2) use of a modified alkaline transfer protocol which increases sensitivity and decreases the autoradiographic exposure period. The method lends itself to handling multiple samples containing minimal amounts of starting material, requires equipment commonly found in a clinical laboratory, and yields results within 36 h of specimen receipt. Accordingly, these procedures may find utility in the establishment of molecular diagnostics in a conventional clinical setting.

Blotting, Southern↗
PubMed2006

Comparison of preservation methods of Rhipicephalus appendiculatus (Acari: Ixodidae) for reliable DNA amplification by PCR.

Five differently preserved groups of adult Rhipicephalus appendiculatus specimens were compared for quality of DNA extracted. Three methods were used to extract DNA from specimens i.e. two simple mosquito validated DNA extraction methods and a tick validated method. Extraction of DNA from tick legs was attempted. The quality of DNA extracted was evaluated by the success of PCR amplification of the ITS2 gene and the mitochondrial COI gene fragment. Fresh specimens (i.e. killed just before extraction) had the highest success of DNA amplification followed by specimens killed in ethanol and subsequently stored in the refrigerator (4 degrees C). There was no significant difference in amplification success between cryopreserved and 70% ethanol preserved specimens. It was possible to amplify DNA from legs of ticks. Sequenced ITS2 amplicon of template obtained from legs of ticks was as legible as those from whole tick extract. The two mosquito validated DNA extraction methods showed a significantly lower amplification success than the tick validated protocol.

Animals↗
PubMed2006

Safe Mycobacterium tuberculosis DNA extraction method that does not compromise integrity.

Concern has been raised about the efficacy of the heat killing of mycobacteria during the isolation of DNA. We demonstrate a method that allows for the efficient killing of Mycobacterium tuberculosis without compromising DNA integrity for subsequent molecular investigation. This method reduces the risk of infection to the research scientist.

Bacteriological Techniques↗
PubMed1998

Use of a cysteine proteinase from Carica candamarcensis as a protective agent during DNA extraction.

We describe the use of a plant cysteine proteinase isolated from latex of Carica candamarcensis as a protective agent during isolation of bacterial DNA following growth in culture of these cells. Between 100 to 720 units of proteinase (1 microgram = 6 units) afforded good DNA protection when incubated with various kinds of microorganisms. Agarose gel electrophoresis showed that the resulting DNA was similar in size to DNA preparations obtained by treatment with proteinase K. The viability of the resulting material was checked by PCR amplification using species-specific primers. After standing at room temperature (25 degrees C) for 35 days, the enzyme lost 10% of its initial activity. The enzyme stability and good yield of DNA suggest the use of this proteinase as an alternative to proteinase K.

Animals↗
PubMed1998

Mitochondrial DNA extraction and typing from isolated dentin-experimental evaluation in a Korean population.

This study reports mtDNA polymorphisms in both hypervariable segments HV1 and HV2 of the non coding D-loop region from 60 unrelated Koreans. In contrast to two previous Korean data base studies, mtDNA was extracted separately from pulp tissue and root dentin of teeth obtained from dentists. Dentin turned out to be a reliable source of mitochondrial DNA. This can be of practical importance in forensic identification case work after a long post-mortem interval since pulp decomposes rapidly. The extraction method is explained in detail. The mtDNA polymorphisms obtained from 60 teeth of unrelated Koreans were compared with the already existing Korean data base.

Asian People↗
PubMed2000

K-ras and p53 mutations in DNA extracted from colonic epithelial cells exfoliated in faeces of patients with colorectal cancer.

BACKGROUND: Exfoliated colonic epithelial cells in faeces provide a source of human DNA which may be analysed for the presence of tumour-induced modification. AIM: In the present study we investigated K-ras and p53 mutations in faeces of patients with colorectal carcinoma, to verify whether analysis of these mutations might identify a high percentage of patients with colorectal cancer. PATIENTS AND METHODS: Faeces, tumour and normal mucosa samples were taken from 26 patients. Polymerase chain reaction amplification and restriction enzyme analysis were performed to detect K-ras mutations; p53 gene mutations were identified by using polymerase chain reaction amplification and single strand conformation polymorphism. RESULTS: We were able to amplify the K-ras gene and exons 5-9 of the p53 gene in 100% of the faecal samples studied. K-ras and p53 gene mutations were detected in faeces in 26.9% and 50% of the cases, respectively. The two mutations were present together in 5 out of 26 patients. There was full agreement between the K-ras and p53 pattern observed in faecal DNA and that in tumour tissue DNA. CONCLUSIONS: Application of K-ras and p53 mutation gene analysis in the faeces may have clinical applications in the future. Since this genetic analysis is able to detect only 57.7% of patients with colorectal cancer, the study of other genes involved in colorectal carcinogenesis is necessary.

Adenocarcinoma↗
PubMed1991

Methods for viral isolation and DNA extraction for a penaeid shrimp baculovirus.

Procedures for the purification of virions and nucleocapsids of Baculovirus penaei (BP) of penaeid shrimp and subsequent extraction of the viral nucleic acid are described. BP-infected hepatopancrata, from two species of shrimp from different geographical locations in the Americas, were removed and homogenized in a solution of TN buffer (0.01 M Tris-HCl, 0.10 M NaCl, pH 8.0). The homogenized mixture was strained through a 100-mesh screen to remove large pieces of tissue and centrifuged to concentrate the remaining material. The pellet was suspended in TN buffer and layered on to a handmade CsCl gradient. Fractions were collected according to the bands observed in the gradient, and the optical density at 254 nm was recorded for each fraction. The resultant data was tabulated and graphed. Additionally, each fraction was examined by transmission electron microscopy to determine relative numbers of viral particles present. Large amounts of virus consistently corresponded to a specific band in the gradient, which produced a peak when the spectrophometric data was graphed. Nucleic acid was then extracted from the purified viral particles. Removal of polysaccharides was accomplished with the addition of CTAB/NaCl. The BP DNA was visualized on an agarose gel with phage lambda DNA markers for size estimation, and a preliminary endonuclease digestion was performed using BamHI.

Animals↗